JP2020154021A - Image forming apparatus and image forming method - Google Patents

Abstract

To provide an image forming apparatus that can achieve both a higher level of low-temperature fixability of toner and extension of the life of an image carrier.SOLUTION: An image forming apparatus comprises an image carrier and developing means that visualizes a latent image formed on a surface of the image carrier with a toner. The image carrier has a Martens hardness of 185 to 250 N/m2. Under an environment of 32°C and 40%RH with a loading rate of 3.0×10-5 N/sec, when the average value of the amount of deformation of the toner caused by micro indentation when a load reaches 3.00×10-4 N is X[μm], and the number average particle diameter of the toner is Dn[μm], 0.13≤X/Dn≤0.16 is satisfied. Further, the toner includes silica fine particles as an external additive and fine particles containing strontium titanate as a main component, and the fine particles containing strontium titanate as a main component contains a third element M selected from La, Mg, Ca, Sn and Si.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image forming apparatus and an image forming method.

Conventionally, in an electrophotographic image forming apparatus or the like, an electrically or magnetically formed latent image is visualized by an electrophotographic toner (hereinafter, may be simply referred to as “toner”). .. For example, in the electrophotographic method, a static charge image (latent image) is formed on the photoconductor, and then the latent image is developed with toner to form a toner image. The toner image is usually transferred onto a transfer material such as paper and then fixed onto a transfer material such as paper. In the fixing step of fixing the toner image on the transfer paper, a heat fixing method such as a heating roller fixing method or a heating belt fixing method is widely and generally used because of its high energy efficiency.

In recent years, the demand from the market for speeding up the image forming apparatus and saving energy has become more and more increasing, and there is a demand for a toner capable of providing a high-quality image with excellent low-temperature fixability. In order to achieve low temperature fixability of the toner, there is a method of lowering the softening temperature of the binder resin of the toner. However, when the softening temperature of the binder resin is low, a part of the toner image adheres to the surface of the fixing member at the time of fixing, and this is transferred onto the copy paper, so-called offset (hereinafter, also referred to as hot offset) occurs. It will be easier. In addition, the heat-resistant storage stability of the toner is reduced, and so-called blocking occurs in which toner particles are fused to each other, particularly in a high temperature environment. In addition, there are problems that the toner is fused to the inside of the developing device and the carrier and contaminated even in the developing device, and that the toner is easily filmed on the surface of the photoconductor.

As a technique capable of solving these problems, many toners in which a crystalline resin and an amorphous resin are used in combination have been conventionally proposed (see, for example, Patent Documents 1 and 2). These were excellent in both low-temperature fixability and heat-resistant storage stability as compared with conventional toners made only of amorphous resin. Further, it has been proposed to achieve both constant temperature fixing and heat-resistant storage by using a crosslinked resin having a low softening temperature as the binder resin (see, for example, Patent Document 3). However, if more of these resins are used in order to achieve both constant temperature fixability and heat-resistant storage at a higher level, the toner matrix particles become softer, so the inorganic fine particles used as an external additive should be used accordingly. Need to increase.

However, when the amount of inorganic fine particles externally attached to the toner increases, more inorganic fine particles are released when the photoconductor is developed. The liberated inorganic fine particles wear the photoconductor while staying on the cleaning blade, but the increase of the liberated inorganic fine particles causes the photoconductor surface layer to wear faster. Therefore, from the viewpoint of reducing the load on the global environment, it is required to extend the life of the photoconductor, but there arises a problem that the life is shortened.

On the other hand, it has been proposed to use a crosslinkable material for the surface layer of the photoconductor and to contain a filler to improve the mechanical durability (see, for example, Patent Document 4).
On the other hand, it is known that the liberated inorganic fine particles form the entire photoconductor and cause an abnormal image. It is known that when inorganic fine particles are filmed on a photoconductor, the optical and electrical characteristics of the filmed portion are deteriorated, which causes an abnormal image. Filming becomes more prominent when the amount of inorganic fine particles externally added to the toner is increased.

For the filming of inorganic fine particles on a photoconductor, it has been conventionally proposed to use an abrasive such as alumina, cerium oxide, and strontium titanate (see, for example, Patent Document 5).

However, if the amount of a spherical abrasive such as alumina added is increased for the purpose of eliminating remarkable filming, the polishing action appears strongly, and even if the hardness of the surface layer of the photoconductor is increased, the wear rate increases. .. On the other hand, it was found that the angular-shaped abrasives such as cerium oxide and strontium titanate have little effect on the wear of the photoconductor, but the photoconductor is easily damaged due to its shape.

Therefore, an object of the present invention is to provide an image forming apparatus capable of achieving both a higher level of low temperature fixability of toner and a longer life of an image carrier.

The above problem is solved by the following configuration 1).
1) An image carrier, a charging means for charging the surface of the image carrier, an exposure means for writing an electrostatic latent image on the surface of the charged image carrier, and a latent image formed on the surface of the image carrier with toner. In an image forming apparatus including a developing means for visualizing and a transfer means for transferring a toner image on the surface of the image carrier to a transfer target.
The image carrier has a Martens hardness of 185 to 250 N / m ² .
The toner has a load speed of 3.0 × 10 ^-5 N / sec under an environment of 32 ° C. and 40% RH, and the amount of deformation due to micro-pushing when the load reaches 3.00 × 10 ^-4 N. Assuming that the average value is X [μm] and the number average particle size is Dn [μm], the formula 0.13 ≦ X / Dn ≦ 0.16 is satisfied.
The toner further contains silica fine particles and strontium titanate-based fine particles as an external additive, and the strontium titanate-based fine particles are further derived from La, Mg, Ca, Sn and Si. An image forming apparatus comprising a selected third element M.

According to the present invention, it is possible to provide an image forming apparatus capable of achieving both a higher level of low temperature fixability of toner and a longer life of an image carrier.

It is schematic cross-sectional view which shows the structural example in one Embodiment of the image forming apparatus which concerns on this invention. It is schematic cross-sectional view which shows the structural example in the other embodiment of the image forming apparatus which concerns on this invention. It is an enlarged view of the main part which shows the structural example of the image forming means of each color in the image forming apparatus shown in FIG. It is schematic cross-sectional view which shows an example of the structure of the process cartridge which is detachably used in the image forming apparatus which concerns on this invention.

Hereinafter, embodiments of the present invention will be described in more detail.
The image forming apparatus of the present invention
(A) Toner is an image carrier, a charging means for charging the surface of the image carrier, an exposure means for writing an electrostatic latent image on the surface of the charged image carrier, and a latent image formed on the surface of the image carrier. In an image forming apparatus including a developing means for visualizing with, and a transfer means for transferring a toner image on the surface of the image carrier to a transfer target.
(B) The image carrier has a Martens hardness of 185 to 250 N / m ² .
(C) The toner is pressed into a small amount when the load reaches 3.00 × 10 ^-4 N at a load speed of 3.0 × 10 ^-5 N / sec in an environment of 32 ° C. and 40% RH. Assuming that the average value of the amount of deformation is X [μm] and the number average particle size is Dn [μm], the formula 0.13 ≤ X / Dn ≤ 0.16 is satisfied.
(D) The toner further contains silica fine particles and fine particles containing strontium titanate as a main component as an external additive, and (e) the fine particles containing strontium titanate as a main component further contain La, Mg, and It is characterized by containing a third element M selected from Ca, Sn and Si.

In the above configuration (b), in the present invention, it is necessary that the Martens hardness of the image carrier is 185 to 250 N / m ² . By setting the Martens hardness of the image carrier in the above range, the wear rate of the image carrier can be suppressed and the life of the image carrier can be extended, and the external additive on the image carrier can be used as described later. Even if the number is large, the damage to the image carrier can be effectively suppressed. In the present invention, it is more preferable to set the Martens hardness of the image carrier in the range of 200 to 250 N / m ² because the damage to the image carrier can be further suppressed.

The Martens hardness in the present invention is measured by the method described in the following Examples.
Hereinafter, the image carrier may be referred to as a photoconductor.

In the above configuration (c), in the present invention, the toner has a load rate of 3.0 × 10 ^-5 N / sec and a load of 3.00 × 10 ^-4 N under an environment of 32 ° C. and 40% RH. Assuming that the average value of the amount of deformation due to micro-pushing when the value is reached is X [μm] and the number average particle size is Dn [μm], it is necessary to satisfy the formula 0.13 ≦ X / Dn ≦ 0.16.
For example, the toner is fixed on the paper to be transferred by the fixing roller in the fixing process, but it is not only softened by the heat of the fixing roller but also deformed appropriately by the pressure applied by the fixing nip, so that it has low temperature fixability. Can be greatly improved. It is considered that this is because the contact area between the paper and the toner increases due to the appropriate deformation of the toner at the fixing nip, and the contact area between the fixing roller and the toner increases so that the toner can acquire more heat. ..

The amount of deformation due to the minute indentation is such that the load speed is 3.0 × 10 ^-5 N / sec in an environment of 32 ° C. and 40% RH, and the amount of deformation due to the minute indentation reaches 3.00 × 10 ^-4 N. It is the amount of deformation due to, and under this condition, the ease of deformation of the toner during fixing can be expressed. The environment is 32 ° C, which is lower than the glass transition temperature of the toner and begins to be affected by the temperature in order to obtain high sensitivity, and the deformation amount may be affected by the humidity differently depending on the toner. The moderate relative humidity is 40%. Loading rate and load, time scale in the fixing, the pressure applied to the toner at the fixing nip, taking into account the stability of the measurement, the load rate is 3.0 × ¹⁰ -5 N / sec, load 3.00 × 10 ^- It is ⁴ N. In order to eliminate the influence of the toner particle size on the deformation amount, the value obtained by dividing the average value X [μm] of the deformation amount by the number average particle size by Dn [μm] is used as an index.

When X / Dn is in the range of 0.13 ≦ X / Dn ≦ 0.16, it is possible to achieve both low temperature fixability of the toner at a higher level and durability against pressure stress. When X / Dn is less than 0.13, the toner is less likely to be deformed due to pressure stress in the developing section and the durability of the toner can be improved, while the toner is less likely to be deformed at the fixing nip and the low temperature fixability is improved. Is impaired. On the other hand, when it is larger than 0.16, the low temperature fixability can be improved, but the durability of the toner is impaired even if a large amount of the external additive is contained.

In order to control X / Dn to 0.13 ≦ X / Dn ≦ 0.16, the physical properties of the binder resin of the toner may be controlled. As a method for controlling the physical properties of the binder resin, for example, adjustment of the glass transition temperature of an amorphous resin having no crosslinked structure, use of an amorphous resin having a crosslinked structure and adjustment of the glass transition temperature and content, Examples include the use of crystalline resin and adjustment of the content. The lower the glass transition temperature of the amorphous resin, the larger the amount of deformation, and the higher the content of the crystalline resin, the larger the amount of deformation.

In the present invention, by setting X / Dn to 0.15 ≦ X / Dn ≦ 0.16, the low temperature fixability of the toner and the durability against pressure stress can be further improved.

The X / Dn in the present invention is measured by the method described in the following examples.

In the above configurations (d) and (e), in the present invention, silica fine particles and strontium titanate-based fine particles are further contained as an external additive, and the strontium titanate-based fine particles are further La. , Mg, Ca, Sn and Si need to contain a third element M selected from.
The fine particles containing strontium titanate as a main component are fine particles containing strontium titanate and having an element ratio of 50% or more. Strontium titanate has been conventionally used as an abrasive because of its characteristic hardness (Mohs hardness 5 to 6) and angular shape. In the present invention, silica fine particles contained in the toner are released to the photoconductor. It is necessary to scrape off the filming caused by sticking.

When the third element M is contained in the fine particles containing strontium titanate as a main component, the characteristic angular shape becomes a slightly rounded shape. The angular shape of the fine particles that do not contain the third element M is likely to damage the photoconductor, but by adding the third element M to the fine particles to form a rounded shape, the scratches on the photoconductor are effective. Can be suppressed.

Further, in the present invention, the fine particles containing strontium titanate as a main component have an average particle diameter of 30 nm or more, and an arbitrary point on the contour of the fine particles is set as a reference point A in the projected image of the fine particles. A point on the contour of the fine particles located at a linear distance of 15 nm in one direction from the point A is defined as a point B, and a point on the contour of the fine particles located at a linear distance of 15 nm in the other direction from the reference point A is defined as a point B. When the point C is taken, it is preferable that the average value of the smallest radius R of the circumscribed circles of the triangle formed by the points A, B and C is 11 to 13 nm.
The radius of the circumscribed circle of the triangle is a substitute for the radius of curvature in the region, and the smaller the radius, the steeper the curve, and conversely, the larger the radius, the gentler the curve. The radius R in one particle represents the degree of sharpness at the most sharp point of the particle, and if the average value of the radius R is in the range of 11 to 13 nm, the degree of sharpness is appropriate and the most effective. Demonstrate. When the average value of the radius R is 11 nm or more, the degree of sharpness does not become steep, that is, the shape does not become angular, and damage to the photoconductor is suppressed. Further, when the average value of the radius R is 13 nm or less, the gentleness of the sharpness becomes appropriate and the polishing action becomes appropriate, so that the wear rate of the photoconductor can be suppressed. Further, when the average particle diameter is smaller than 30 nm, the particles tend to be rounded, so that the average value of the radius R exceeds 13 nm. When the average particle size is 30 nm or more and the average value of the radius R is 11 nm to 13 nm, the filming of the external additive is effectively scraped off while suppressing the abrasion rate of the photoconductor and the occurrence of scratches. be able to. Further, among the fine particles containing strontium titanate as a main component, the particles satisfying the average value of 11 to 13 nm of the minimum radius R more preferably occupy 70% by mass or more. The average particle size of the fine particles containing strontium titanate as a main component is preferably 20 nm to 150 nm, more preferably 30 nm to 70 nm.
The radius R is measured by the method described in the following examples.

Further, in the present invention, the coverage of the external additive to the toner is preferably 40 to 70%, so that the surface of the toner matrix particles is sufficiently covered by the coverage of 40 to 70%. It can be made resistant to stress such as pressurization and heat. When the toner base particles contain a large amount of crystalline resin or the like in order to exhibit more excellent low-temperature fixability, the toner durability is improved when the coverage is 40% or more. On the other hand, when the coverage is 70% or less, the external additive does not hinder the fixation, the low-temperature fixability is improved, the release of the external additive to the photoconductor is suppressed, and filming is prevented. It is possible, and the wear of the photoconductor is also suppressed.

In the present invention, when the above 0.15 ≦ X / Dn ≦ 0.16 is satisfied and the coverage of the external additive satisfies 55 to 70%, the low temperature fixability and durability can be further improved.

The coverage of the external additive is measured by the method described in the following Examples.

In the present invention, it is necessary to combine the above configurations (b) to (e), which makes it possible to achieve both a higher level of low temperature fixability of the toner and a longer life of the photoconductor. According to the study by the present inventors, the use of fine particles containing strontium titanate as a main component, which has an angular shape, damages the photoconductor, while changing the shape to a rounded shape causes the photoconductor to have a rounded shape. Scratches can be suppressed. However, if a toner containing a large amount of an additive is used in order to achieve a high level of low-temperature fixability and durability of the toner, even if the shape of the fine particles containing strontium titanate as the main component is rounded, the photoconductor There are scratches on the top. On the other hand, by combining the above configurations (b) to (e), a dramatic improvement was obtained. The details of the mechanism are unknown, but the present inventors consider it as follows.
As the amount of the external additive contained in the toner increases, the release of the external additive to the photoconductor increases. The wear of the photoconductor progresses due to this released external additive, but it is considered that the wear is uneven and unevenness occurs at a fine level on the order of nm. If the external additive enters the locally recessed portion of the photoconductor, the friction between the external additive and the photoconductor is large because there are many contact areas, and it is assumed that the photoconductor is likely to be scratched. Therefore, when a large amount of an additive is contained in the toner, even if fine particles containing strontium titanate as a main component in a rounded shape are used, scratches occur on the photoconductor. On the other hand, as in the present invention, by specifying the maltens hardness of the photoconductor, the amount of deformation of the toner, and the composition of the fine particles containing strontium titanate as the main components as described above, local dents in the photoconductor are suppressed. It is possible to prevent scratches on the photoconductor, suppress wear of the photoconductor, extend the life of the photoconductor, and achieve a higher level of low-temperature fixability of the toner.

Next, the toner that can be used in the present invention will be described.

<Toner base>
The toner base can contain a binder resin and, if necessary, other components.

<Bundling resin>
The binder resin may contain an amorphous resin, and may contain a crystalline resin if necessary.
The amorphous resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, acrylic resin, styrene-acrylic resin, polyester resin, epoxy resin and the like can be selected, but polyester resin. Is preferable. If necessary, two or more types may be used in combination.
The amorphous polyester resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a polycondensation polyester resin synthesized from a polyhydric alcohol and a polyvalent carboxylic acid.
As the amorphous polyester resin, an amorphous polyester resin having a divalent aliphatic alcohol component and a polyvalent aromatic carboxylic acid component as constituent components is preferable.
Examples of the polyhydric alcohol include divalent diols, trivalent to octavalent or higher polyols, and the like.

The divalent diol is not particularly limited and may be appropriately selected depending on the intended purpose. For example, an aliphatic alcohol such as a linear aliphatic alcohol or a branched aliphatic alcohol (divalent aliphatic alcohol). ) And so on. Among these, an aliphatic alcohol having 2 to 36 chain carbon atoms is preferable, and a linear aliphatic alcohol having 2 to 36 chain carbon atoms is more preferable. These may be used alone or in combination of two or more.

The linear aliphatic alcohol is not particularly limited and may be appropriately selected depending on the intended purpose. For example, ethylene glycol, 1,3-propanediol, 1,4-butanediol and 1,5-pentane can be selected. Diol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol , 1,13-Tridecanediol, 1,14-Tetradecanediol, 1,18-Octadecanediol, 1,20-Eicosandiol and the like. Of these, ethylene glycol, 1,3-propanediol (propylene glycol), 1,4-butanediol, 1,6-hexanediol, 1,9-nonanediol, and 1,10-decane are considered in terms of availability. Diol is preferred. Among these, linear aliphatic alcohols having 2 to 36 chain carbon atoms are preferable.

Examples of the polycarboxylic acid include a dicarboxylic acid and a trivalent to hexavalent or higher polycarboxylic acid. Of these, polyvalent aromatic carboxylic acids are preferable.

The dicarboxylic acid is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include aliphatic dicarboxylic acid and aromatic dicarboxylic acid. Examples of the aliphatic dicarboxylic acid include a linear aliphatic dicarboxylic acid and a branched aliphatic dicarboxylic acid. Among these, a linear aliphatic dicarboxylic acid is preferable.

The aliphatic dicarboxylic acid is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include alkanedicarboxylic acid, alkenylsuccinic acid, alkenedicarboxylic acid and alicyclic dicarboxylic acid.
Examples of the alkanedicarboxylic acid include an alkanedicarboxylic acid having 4 to 36 carbon atoms. Examples of the alkanedicarboxylic acid having 4 to 36 carbon atoms include succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, octadecanedicarboxylic acid, and decylsuccinic acid.
Examples of the alkenyl succinic acid include dodecenyl succinic acid, pentadecenyl succinic acid, octadecenyl succinic acid and the like.
Examples of the alkene dicarboxylic acid include alkene dicarboxylic acids having 4 to 36 carbon atoms. Examples of the alkenedicarboxylic acid having 4 to 36 carbon atoms include maleic acid, fumaric acid, citraconic acid and the like.
Examples of the alicyclic dicarboxylic acid include an alicyclic dicarboxylic acid having 6 to 40 carbon atoms. Examples of the alicyclic dicarboxylic acid having 6 to 40 carbon atoms include dimer acid (dimerized linoleic acid).

The aromatic dicarboxylic acid is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include aromatic dicarboxylic acids having 8 to 36 carbon atoms. Examples of the aromatic dicarboxylic acid having 8 to 36 carbon atoms include phthalic acid, isophthalic acid, terephthalic acid, t-butylisophthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4'-biphenyldicarboxylic acid. Be done.

Examples of the trivalent to hexavalent or higher polycarboxylic acid include aromatic polycarboxylic acids having 9 to 20 carbon atoms. Examples of the aromatic polycarboxylic acid having 9 to 20 carbon atoms include trimellitic acid and pyromellitic acid.

As the dicarboxylic acid or the trivalent to hexavalent or higher polyvalent carboxylic acid, the above-mentioned acid anhydride or an alkyl ester having 1 to 4 carbon atoms may be used. Examples of the alkyl ester having 1 to 4 carbon atoms include methyl ester, ethyl ester, and isopropyl ester.

The weight average molecular weight of the amorphous polyester resin is usually 3,000 to 10,000, preferably 4,000 to 7,000. When the weight average molecular weight of the amorphous polyester resin is 3,000 or more, the heat-resistant storage stability and durability of the toner can be improved, and when it is 10,000 or less, the low-temperature fixability of the toner is improved. Can be made to.

The acid value of the amorphous polyester resin is usually 1 to 50 mgKOH / g, preferably 5 to 30 mgKOH / g. When the acid value of the amorphous polyester is 1 mgKOH / g or more, the toner tends to be negatively charged, and the low temperature fixability of the toner can be improved. When the acid value is 50 mgKOH / g or less, the toner is charged. Stability, especially charge stability against environmental changes, can be improved.

The hydroxyl value of the amorphous polyester resin is usually 5 mgKOH / g or more.

The glass transition temperature of the amorphous polyester resin is usually 40 to 80 ° C, preferably 50 to 70 ° C. When the glass transition temperature of the amorphous polyester resin is 40 ° C. or higher, the heat-resistant storage stability, durability and filming resistance of the toner can be improved, and when the temperature is 80 ° C. or lower, the toner is fixed at a low temperature. The sex can be improved.

The content of the amorphous polyester resin in the toner is usually 50% by mass or more, preferably 50 to 90% by mass, and more preferably 60 to 80% by mass. When the content of the amorphous polyester resin in the toner is 50% by mass or more, it is possible to suppress the occurrence of image fog and distortion, and when it is 90% by mass or less, the low temperature fixability of the toner is improved. Can be improved.

The crystalline resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, acrylic resin, styrene-acrylic resin, polyester resin, epoxy resin and the like can be selected. preferable.
Since the crystalline polyester resin has high crystallinity, it exhibits a thermal melting property in which the viscosity sharply decreases in the vicinity of the fixing start temperature. Therefore, the crystalline polyester resin does not melt until just before the melting start temperature, and the heat-resistant storage property is excellent. At the melting start temperature, the crystalline polyester resin melts, so that the viscosity rapidly decreases, and the crystalline polyester resin is compatible with the amorphous resin and fixed. Therefore, a toner having excellent heat-resistant storage stability and low-temperature fixability can be obtained. Further, a toner having a large difference in the mold release width, that is, the fixing lower limit temperature and the high temperature offset generation temperature can be obtained.

The crystalline polyester resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a polycondensation polyester resin synthesized from a polyhydric alcohol and a polyvalent carboxylic acid.
Instead of the polyvalent carboxylic acid, an anhydride of the polyvalent carboxylic acid, a lower alkyl ester having 1 to 3 carbon atoms or a halide may be used.

The polyhydric alcohol is not particularly limited, and examples thereof include diols, trihydric or higher alcohols, and two or more kinds may be used in combination.

Examples of the diol include saturated aliphatic diols.

Examples of the saturated aliphatic diol include a linear saturated aliphatic diol and a branched saturated aliphatic diol. Among them, a linear saturated aliphatic diol is preferable because the crystallinity of the crystalline polyester resin is high, and a linear saturated aliphatic diol having 2 to 12 carbon atoms is more preferable because it is easily available.

Saturated aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, and 1,8-octane. Diol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecane Diol, 1,14-eicosandecandiol and the like can be mentioned. Among them, ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, and 1,10-decane are excellent because the crystalline polyester resin has high crystallinity and excellent sharp meltability. Diol, 1,12-dodecanediol is preferred.

Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like.

The polyvalent carboxylic acid is not particularly limited, and examples thereof include a divalent carboxylic acid and a trivalent or higher carboxylic acid.

Examples of the divalent carboxylic acid include oxalic acid, succinic acid, glutaric acid, adipic acid, speric acid, azelaic acid, sebacic acid, 1,9-nonandicarboxylic acid, 1,10-decandicarboxylic acid, and 1,12-dodecane. Saturated aliphatic dicarboxylic acids such as dicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid; phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, mesaconic acid, etc. Examples thereof include aromatic dicarboxylic acids such as dibasic acid.

Examples of the trivalent or higher valent carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid and the like.

The polyvalent carboxylic acid may contain a dicarboxylic acid having a sulfonic acid group.

Further, the polyvalent carboxylic acid may contain a dicarboxylic acid having a carbon-carbon double bond.

The crystalline polyester resin preferably has a structural unit derived from a linear saturated aliphatic dicarboxylic acid having 4 to 12 carbon atoms and a structural unit derived from a linear saturated aliphatic diol having 2 to 12 carbon atoms. As a result, the crystalline polyester has high crystallinity and is excellent in sharp meltability. As a result, the low temperature fixability of the toner can be improved.

The weight average molecular weight of the crystalline polyester resin is usually 3,000 to 30,000, preferably 5,000 to 15,000. When the weight average molecular weight of the crystalline polyester resin is 3,000 or more, the heat-resistant storage stability of the toner can be improved, and when it is 30,000 or less, the low-temperature fixability of the toner can be improved. ..

The acid value of the crystalline polyester resin is usually 5 mgKOH / g or more, preferably 10 mgKOH / g or more. Thereby, the low temperature fixability of the toner can be improved. On the other hand, the acid value of the crystalline polyester resin is usually 45 mgKOH / g or less. Thereby, the high temperature offset resistance of the toner can be improved.

The hydroxyl value of the crystalline polyester resin is usually 50 mgKOH / g or less, preferably 5 to 50 mgKOH / g. When the hydroxyl value of the crystalline polyester resin is 50 mgKOH / g or less, the low temperature fixability and charging characteristics of the toner can be improved.

The melting point of the crystalline polyester resin is usually 60 to 90 ° C, preferably 60 to 80 ° C. When the melting point of the crystalline polyester resin is 60 ° C. or higher, the heat-resistant storage stability of the toner can be improved, and when the melting point is 90 ° C. or lower, the low-temperature fixability of the toner can be improved.

The molecular structure of the crystalline polyester resin can be confirmed by NMR measurement using a solution or a solid, X-ray diffraction, GC / MS, LC / MS, IR measurement, or the like. Conveniently, in the infrared absorption spectrum, a polyester having absorption based on δCH (out-of-plane bending vibration) of an olefin at 965 ± 10 cm ^-1 or 990 ± 10 cm ^-1 can be detected as a crystalline polyester.

The content of the crystalline polyester resin in the toner is usually 3 to 15% by mass, preferably 5 to 10% by mass. When the content of crystalline polyester in the toner is 3% by mass or more, the low-temperature fixability of the toner can be improved, and when it is 15% by mass or less, the heat-resistant storage stability of the toner is improved and the heat-resistant storage stability of the toner is improved. It is possible to suppress the occurrence of image fog.

Examples of other components of the toner base include a mold release agent, a colorant, a charge control agent, a cleaning property improver, a magnetic material, and the like.

The release agent is not particularly limited, but is limited to plant wax (for example, carnauba wax, cotton wax, wood wax, rice wax), animal wax (for example, honey wax, lanolin), and mineral wax (for example, ozokelite, celsine). ), Petroleum wax (eg paraffin, microcrystallin, petrolatum), hydrocarbon wax (eg Fisher Tropsch wax, polyethylene wax, polypropylene wax), synthetic wax (eg ester, ketone, ether), fatty acid amide compound (For example, 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide and the like can be mentioned. Among them, hydrocarbon waxes such as paraffin wax, microcrystallin wax, Fisher Tropsch wax, polyethylene wax and polypropylene wax are preferable. ..

The melting point of the release agent is usually 60 to 80 ° C. When the melting point of the release agent is 60 ° C. or higher, the heat-resistant storage stability of the toner can be improved, and when the melting point is 80 ° C. or lower, the high-temperature offset resistance of the toner can be improved.

The content of the release agent in the toner is usually 2 to 10% by mass, preferably 3 to 8% by mass. When the content of the release agent in the toner is 2% by mass or more, the high temperature offset resistance and low temperature fixability of the toner can be improved, and when it is 10% by mass or less, the heat storage property of the toner is stored. Can be improved and the occurrence of image fogging can be suppressed.

The colorant is not particularly limited, but is carbon black, niglosin dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, yellow clay, yellow lead, titanium yellow, polyazo. Yellow, Oil Yellow, Hansa Yellow (GR, A, RN, R), Pigment Yellow L, Benzidine Yellow (G, GR), Permanent Yellow (NCG), Balkan Fast Yellow (5G, R), Tartragin Lake, Kinolin Yellow Lake, Anthracan Yellow BGL, Isoindolinon Yellow, Bengala, Lead Tan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Faise Red, Parachloro Ortho Nitroaniline Red, Resole Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmin BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resole Rubin GX, Permanent Red F5R, Brilliant Carmin 6B, Pigment Scarlet 3B, Bordeaux 5B, Truisin Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bonmaroon Light, Bonmaroon Medium, Eosin Lake, Rhodamin Lake B, Rhodamin Lake Y, Alizarin Lake, Thioinjigo Red B, Thioinjigo Maroon , Oil Red, Kinacridon Red, Pyrazolon Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinon Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal-free Phtalocyanin Blue, Phtalocyanin Blue, Fast Sky Blue, Indan Slen Blue (RS, BC), Indigo, Ultramarine, Navy Blue, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zink Green , Chromium oxide, Pyridian, Emerald green, Pigment green B, Naftor green B, Green gold, Acid green rake, Malakite green rake, Phtalocyanin green, Anthracy Non-green, titanium oxide, zinc oxide, lithopone and the like may be mentioned, and two or more kinds may be used in combination.

The content of the colorant in the toner is usually 1 to 15% by mass, preferably 3 to 10% by mass.

The pigment can also be combined with a resin and used as a masterbatch.

The resin is not particularly limited, but is a polymer of styrene such as amorphous polyester resin, polystyrene, polyp-chlorostyrene, polyvinyltoluene or a substitute thereof; styrene-p-chlorostyrene copolymer and styrene-propylene. Styrene, styrene-vinyltoluene copolymer, styrene-vinylnaphthalin copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-acrylic acid Octyl copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer , Styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-inden copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, etc. Styrene-based copolymers; polymethylmethacrylate, polybutylmethacrylate, polyvinyl chloride, polyvinylacetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid, rosin, modified Examples thereof include rosin, sterene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin and the like, and two or more thereof may be used in combination.

A masterbatch can be produced by mixing and kneading the resin and the pigment. At this time, an organic solvent can be used in order to enhance the interaction between the pigment and the resin.

Further, a masterbatch is manufactured by using a so-called flushing method, in which an aqueous paste of a pigment is mixed and kneaded together with a resin and an organic solvent, the pigment is transferred to the resin side, and water and the organic solvent are removed. May be good. In this case, since the wet cake of the pigment can be used as it is, it is not necessary to dry the pigment.

The apparatus for mixing and kneading is not particularly limited, and examples thereof include a high shear dispersion apparatus such as a three-roll mill.

The cleaning property improving agent is not particularly limited, and examples thereof include fatty acid metal salts such as zinc stearate and calcium stearate, and polymer particles produced by soap-free emulsion polymerization such as polymethylmethacrylate particles and polystyrene particles.

The volume average particle size of the polymer particles is usually 0.01 to 1 μm.

The magnetic material is not particularly limited, and examples thereof include iron, magnetite, and ferrite. Of these, a white material is preferable in terms of color tone.

<External agent>
In the present invention, the toner contains silica fine particles and fine particles containing strontium titanate as a main component as an external additive. In addition, if necessary, an external additive other than the above may be used in combination, and oxide particles (for example, titania particles, tin oxide particles, antimony oxide particles), fatty acid metal salts (for example, zinc stearate, aluminum stearate) may be used in combination. ), Fluoropolymer particles and the like are preferably used. From the viewpoint of hydrophobization, it is preferable that the surface of the fine particles is coated with an organic compound as described below.

The method for producing fine particles containing strontium titanate as a main component is not particularly limited as long as it can achieve the properties required for the present invention, and examples thereof include a hydrothermal treatment method using a pressurized container and a normal pressure heating reaction method. Be done.

In the case of the atmospheric heating reaction method, the mineral acid deflated product of the hydrolyzate of the titanium compound, the water-soluble compound containing strontium, and the water-soluble component M selected from La, Mg, Ca, Sn and Si. The compounds are mixed to prepare a mixed solution in which the amount of the third component M added is equivalent to, for example, 2 mol% to 15 mol% with respect to strontium, and the temperature is adjusted to 70 ° C. or higher and 100 ° C. or lower while adding an alkaline aqueous solution to the mixed solution. It is produced by heating to synthesize strontium titanate-based particles, and then treating the obtained strontium titanate-based particles with an acid.

In the atmospheric heating reaction method, an inorganic acid deflated product of a titanium compound can be used as a titanium oxide source, and strontium nitrate, strontium chloride, strontium hydroxide, or the like can be used as a strontium source. Examples of the water-soluble compound of the third component M include lanthanum nitrate, lanthanum chloride, lanthanum hydroxide, magnesium nitrate, magnesium chloride, magnesium hydroxide, calcium nitrate, calcium chloride, calcium hydroxide, tin chloride, and sodium silicate. Sodium silicate and the like can be preferably used. As the alkaline aqueous solution, caustic alkali can be used, but among them, the sodium hydroxide aqueous solution is preferable.

Factors that affect the particle size of the obtained strontium titanate-based fine particles in the above-mentioned production method include the mixing ratio of the raw materials at the time of the reaction, the concentration of the titanium oxide source at the initial stage of the reaction, and the addition of an alkaline aqueous solution. Examples include temperature and addition rate. Further, as a factor affecting the fine particle particle shape containing strontium titanate as a main component, for example, the radius R, there is an addition amount of the third component M, which is appropriately adjusted to obtain a desired particle diameter and particle shape. can do. In addition, in order to prevent the formation of strontium carbonate in the reaction process, it is preferable to prevent the mixing of carbon dioxide gas by reacting in a nitrogen gas atmosphere.

The method for hydrophobizing the silica fine particles or the fine particles containing strontium titanate as a main component is not particularly limited, and examples thereof include a method of coating the surface with an organic compound, for example, a method of treating the fine particles with a silane coupling agent. Examples thereof include a method of treating the fine particles with silicone oil, and two or more kinds of treatment agents may be used in combination, or two or more treatment methods may be used in combination.

The silane coupling agent is not particularly limited, and examples thereof include hexamethyldisilazane, methyltrimethoxysilane, methyltriethoxysilane, and octyltrimethoxysilane.

The silicone oil is not particularly limited, but dimethyl silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, methylhydrogen silicone oil, alkyl-modified silicone oil, fluorine-modified silicone oil, polyether-modified silicone oil, alcohol-modified silicone oil, Examples thereof include amino-modified silicone oil, epoxy-modified silicone oil, epoxy-polyether-modified silicone oil, phenol-modified silicone oil, carboxyl-modified silicone oil, mercapto-modified silicone oil, methacryl-modified silicone oil, and α-methylstyrene-modified silicone oil.

The content of the external additive in the toner is usually 0.5 to 8% by mass, and is preferably 3 to 6% by mass in order to achieve both low temperature fixability and durability at a high level.
The amount of silica fine particles as an external additive is preferably 1.5 to 5% by mass with respect to the entire toner. The amount of fine particles containing strontium titanate as a main component as an external additive is preferably 0.05 to 2% by mass with respect to the entire toner.

The average primary particle size of the silica fine particles or the fine particles containing strontium titanate as a main component is usually 10 to 500 nm, preferably 20 to 100 nm. When the average primary particle size of the silica fine particles or the fine particles containing strontium titanate as a main component is 10 nm or more, the burial of these fine particles in the population particles can be suppressed, and when the fine particles are 500 nm or less, the toner can be used. Desorption can be suppressed.

The method for producing the toner matrix particles is not particularly limited, and examples thereof include an ester extension method and the like.

The toner is an oil phase containing an amorphous prepolymer having an isocyanate group, an amorphous polyester resin, a crystalline polyester resin, a mold release agent, a colorant, etc., if necessary, emulsified or dispersed in an aqueous medium. It is preferable to manufacture by.
The toner is an aqueous phase in which an oil phase containing an amorphous polyester prepolymer A having an isocyanate group, an amorphous polyester resin B, a crystalline polyester resin C, a mold release agent, a coloring agent, etc., if necessary, is emulsified. Alternatively, it is preferably produced by dispersing.

It is preferable that the resin particles are dispersed in the aqueous medium.

The resin constituting the resin particles is not particularly limited as long as it can be dispersed in an aqueous medium, but is not particularly limited, but is vinyl-based resin, polyurethane, epoxy resin, polyester, polyamide, polyimide, silicon-based resin, phenol resin, and melamine. Examples thereof include resin, urea resin, aniline resin, ionomer resin, polycarbonate and the like, and two or more kinds may be used in combination. Of these, vinyl-based resins, polyurethanes, epoxy resins, and polyesters are preferable because fine spherical resin particles can be easily obtained.

The mass ratio of the resin particles to the aqueous medium is usually 0.005 to 0.1.

The aqueous medium is not particularly limited, and examples thereof include water and a solvent miscible with water, and two or more of them may be used in combination. Of these, water is preferable.

The solvent that can be miscible with water is not particularly limited, and examples thereof include alcohol, dimethylformamide, tetrahydrofuran, cellosolves, lower ketones and the like.

Examples of the alcohol include methanol, isopropanol, ethylene glycol and the like.

Examples of lower ketones include acetone, methyl ethyl ketone and the like.

The oil phase contains a toner material containing an amorphous polyester prepolymer A having an isocyanate group, an amorphous polyester resin B, a crystalline polyester resin C, a mold release agent, a colorant, and the like, if necessary, in an organic solvent. It can be produced by dissolving or dispersing in.

The boiling point of the organic solvent is usually less than 150 ° C. Thereby, the organic solvent can be easily removed.

The organic solvent is not particularly limited, but toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichlorethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, etc. Ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone and the like may be mentioned, and two or more kinds may be used in combination. Among them, ethyl acetate, toluene, xylene, benzene, methylene chloride, 1,2-dichloroethane, chloroform, carbon tetrachloride and the like are preferable, and ethyl acetate is more preferable.

When the oil phase is emulsified or dispersed in an aqueous medium, the amorphous polyester prepolymer A having an isocyanate group is reacted with a compound having an active hydrogen group to produce an amorphous polyester resin A.

The amorphous polyester resin A can be produced by the following methods (1) to (3).
(1) An oil phase containing an amorphous prepolymer A having an isocyanate group and a compound having an active hydrogen group is emulsified or dispersed in an aqueous medium, and has a compound having an active hydrogen group and an isocyanate group in the aqueous medium. A method for producing an amorphous polyester resin A by subjecting an amorphous prepolymer to an elongation reaction and / or a cross-linking reaction.
(2) The oil phase containing the amorphous prepolymer A having an isocyanate group is emulsified or dispersed in an aqueous medium to which a compound having an active hydrogen group is added in advance, and the compound having an active hydrogen group and isocyanate are mixed in the aqueous medium. A method for producing an amorphous polyester resin A by subjecting an amorphous prepolymer having a group to an elongation reaction and / or a cross-linking reaction.
(3) After the oil phase containing the amorphous prepolymer A having an isocyanate group is emulsified or dispersed in an aqueous medium, a compound having an active hydrogen group is added to the aqueous medium, and the particles are mixed in the aqueous medium. A method for producing an amorphous polyester resin A by subjecting a compound having an active hydrogen group and an amorphous prepolymer having an isocyanate group to an elongation reaction and / or a cross-linking reaction from the interface.

When the compound having an active hydrogen group and the amorphous polyester prepolymer A having an isocyanate group are subjected to an elongation reaction and / or a cross-linking reaction from the interface of the particles, the amorphous polyester is preferentially generated on the surface of the toner to be produced. However, a concentration gradient of amorphous polyester can be formed in the toner.

The time for reacting the compound having an active hydrogen group with the amorphous polyester prepolymer A having an isocyanate group is usually 10 minutes to 40 hours, preferably 2 to 24 hours.

The temperature at which the compound having an active hydrogen group and the amorphous polyester prepolymer A having an isocyanate group are reacted is usually 0 to 150 ° C, preferably 40 to 98 ° C.

A catalyst can be used in reacting the compound having an active hydrogen group with the amorphous polyester prepolymer A having an isocyanate group.

The catalyst is not particularly limited, and examples thereof include dibutyltin laurate and dioctyltin laurate.

The method of emulsifying or dispersing the oil phase in the aqueous medium is not particularly limited, and examples thereof include a method of adding the oil phase to the aqueous medium and dispersing it by shearing force.

The disperser used to emulsify or disperse the oil phase in the aqueous medium is not particularly limited, but is a low-speed shear disperser, a high-speed shear disperser, a friction disperser, a high-pressure jet disperser, and ultrasonic dispersion. Machines and the like can be mentioned. Among them, a high-speed shearing type disperser is preferable because the particle size of the dispersion (oil droplet) can be controlled to 2 to 20 μm.

When a high-speed shearing disperser is used, the rotation speed is usually 1,000 to 30,000 rpm, preferably 5,000 to 20,000 rpm. In the case of the batch method, the dispersion time is usually 0.1 to 5 minutes. The dispersion temperature is usually 0 to 150 ° C., preferably 40 to 98 ° C. under pressure.

The mass ratio of the aqueous medium to the toner material is usually 0.5 to 20, preferably 1 to 10. When the mass ratio of the aqueous medium to the toner material is 0.5 or more, the oil phase can be dispersed well, and when it is 20 or less, it is economical.

The aqueous medium preferably contains a dispersant. Thereby, when the oil phase is emulsified or dispersed in the aqueous medium, the dispersion stability of the oil droplets can be improved, the base particles can be formed into a desired shape, and the particle size distribution can be narrowed.

The dispersant is not particularly limited, and examples thereof include a surfactant, a poorly water-soluble inorganic compound dispersant, a polymer-based protective colloid, and the like, and two or more kinds may be used in combination. Of these, surfactants are preferred.

Examples of the surfactant include anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants and the like. Of these, a surfactant having a fluoroalkyl group is preferable.

Examples of the anionic surfactant include alkylbenzene sulfonate, α-olefin sulfonate, phosphoric acid ester and the like.

After the oil phase is dispersed in the aqueous medium, it is preferable to remove the organic solvent to form the parent particles.

The method for removing the organic solvent is not particularly limited, but is a method of gradually raising the temperature of the aqueous medium in which the oil phase is dispersed to evaporate the organic solvent in the oil droplets, or an aqueous system in which the oil phase is dispersed. Examples thereof include a method of spraying the medium in a dry atmosphere to remove the organic solvent in the oil droplets.

It is preferable that the maternal particles are washed and then dried. At this time, the parent particles may be classified. Specifically, it may be classified by removing fine particles from the mother particles contained in the aqueous medium using a cyclone, a decanter, a centrifuge or the like, or the dried mother particles may be classified.

Toner can be produced by mixing the matrix particles with an external additive and, if necessary, a charge control agent. At this time, by applying a mechanical impact force to the mixture, it is possible to suppress the desorption of the external additive from the surface of the parent particles.

The method of applying a mechanical impact force to the mixture is not particularly limited, but a method of applying an impact force to the mixture by rotating the blades at a high speed, or a method of throwing the mixture into a high-speed moving air stream and particles. Alternatively, a method of applying an impact force to the mixture by colliding the particles with the collision plate can be mentioned.

Commercially available devices that apply mechanical impact force to the mixture include ong mills (manufactured by Hosokawa Micron) and type I mills (manufactured by Nippon Pneumatic) to reduce the crushing air pressure, and hybridization systems. (Manufactured by Nara Machinery Co., Ltd.), Cryptron system (manufactured by Kawasaki Heavy Industries), etc.

The developer contains toner and, if necessary, further components such as carriers.

The developer may be a one-component developer or a two-component developer.

The carrier usually has a protective layer formed on the core material.

The material constituting the core material is not particularly limited, but is a manganese-strontium-based material having a mass magnetization of 50 to 90 emu / g, a manganese-magnesium-based material having a mass magnetization of 50 to 90 emu / g, and a mass magnetization of 100 emu / g. Examples of the above iron, high magnetization materials such as magnetite having a mass magnetization of 75 to 120 emu / g, and low magnetization materials such as copper-zinc type having a mass magnetization of 30 to 80 emu / g can be mentioned, and two or more kinds can be used in combination. May be good.

The volume average particle diameter of the core material is usually 10 to 150 μm, preferably 40 to 100 μm.

The content of the carrier in the two-component developer is usually 90 to 98% by mass, preferably 93 to 97% by mass.

The developer is usually used in a known container.

The container is not particularly limited, and examples thereof include a container having a container body and a cap.

The shape of the container body is not particularly limited, and examples thereof include a cylindrical shape.

The inner peripheral surface of the container body has spiral irregularities, and by rotating the container body, the developer can be transferred to the discharge port side, and part or all of the spiral irregularities have a bellows function. Is preferable.

The material of the container body is not particularly limited, and examples thereof include resins such as polyester, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyacrylic acid, polycarbonate, ABS resin, and polyacetal.

Since the container containing the developing agent is easy to store, transport, etc. and has excellent handleability, it can be detachably attached to a process cartridge, an image forming apparatus, etc., which will be described later, and used for replenishing the developing agent. ..

The developer can be applied to a known image forming apparatus or process cartridge that forms an image by an electrophotographic method such as a magnetic one-component developing method, a non-magnetic one-component developing method, or a two-component developing method.

The photoconductor used in the present invention comprises, for example, a conductive support and at least a photosensitive layer on the conductive support, and further has other configurations if necessary.

<Conductive support>
The conductive support is not particularly limited as long as it exhibits conductivity having a volume resistance value of 10 ¹⁰ Ω · cm or less, and can be appropriately selected depending on the intended purpose. An endless belt (endless nickel belt, endless stainless steel belt, etc.) disclosed in Japanese Patent Application Laid-Open No. 52-36016 may be used.

<Photosensitive layer>
The photosensitive layer is not particularly limited as long as it has the outermost surface layer on the outermost surface, and can be appropriately selected depending on the intended purpose. However, at least the charge generation layer, the charge transport layer, and the outermost surface layer (crosslinked type). A photosensitive layer having a charge transport layer) in this order and, if necessary, another layer is preferable.

<Charge generation layer>
The charge generating layer is a layer containing a charge generating substance having a charge generating function as a main component, and a binder resin can be used in combination as needed. As the charge generating substance, an inorganic material and an organic material can be used.

Examples of the inorganic material include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compound, amorphous silicon and the like. In amorphous silicon, a dangling bond terminated with a hydrogen atom or a halogen atom, or a dope with a boron atom, a phosphorus atom or the like is preferably used.

On the other hand, as the organic material, a known material can be used. For example, phthalocyanine pigments such as metallic phthalocyanine and metal-free phthalocyanine, azulenium salt pigments, methine squarelic acid pigments, azo pigments having a carbazole skeleton, azo pigments having a triarylamine skeleton, azo pigments having a diphenylamine skeleton, and dibenzothiophene skeletons. Azo pigments having a fluorenone skeleton, azo pigments having an oxadiazole skeleton, azo pigments having a bisstylben skeleton, azo pigments having a distyryloxaziazole skeleton, azo pigments having a distyrylcarbazole skeleton, perylene Examples thereof include anthraquinone-based or polycyclic quinone-based pigments, quinoneimine-based pigments, diphenylmethane and triphenylmethane-based pigments, benzoquinone and naphthoquinone-based pigments, cyanine and azomethine-based pigments, indigoid-based pigments, and bisbenzimidazole-based pigments. These charge generating substances can be used alone or as a mixture of two or more kinds.

<Charge transport layer>
The charge transport layer is a layer having a charge transport function, and is a layer containing a charge transport substance or a polymer charge transport substance and a binder resin as main components.

The charge transporting substance is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a known hole transporting substance having a hole transporting structure such as triarylamine, hydrazone, pyrazoline and carbazole, and condensation. Examples thereof include known electron transporting materials having an electron transporting structure such as a polycyclic quinone, a diphenoquinone, a cyano group, and an electron-withdrawing aromatic ring having a nitro group. The hole transporting substance or the electron transporting substance may be used alone or as a mixture of two or more kinds.

<Surface layer>
The surface layer can contain a filler and a binder resin.
As the binder resin, a thermoplastic resin such as a polyarylate resin or a polycarbonate resin, or a crosslinked resin such as a urethane resin or a phenol resin is used.
As the filler, organic fine particles and inorganic fine particles are used, and inorganic fine particles are preferable.

Examples of the organic fine particles include fluorine-containing resin fine particles and carbon-based fine particles.
On the other hand, examples of the inorganic fine particles include metal powders such as copper, tin, aluminum, and indium. Further, metal oxides such as silicon oxide, silica, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, indium oxide doped with tin, and inorganic substances such as potassium titanate. Materials are mentioned. In particular, metal oxides are good, and silicon oxide, aluminum oxide, titanium oxide and the like can be effectively used.

The volume average particle diameter of the inorganic fine particles is preferably 10 to 500 nm from the viewpoint of light transmittance and abrasion resistance of the surface layer.
When the volume average particle size of the inorganic fine particles is 10 nm or more, the decrease in wear resistance and the decrease in dispersibility are suppressed, and when the volume average particle size is 500 nm or less, the sedimentation property of the inorganic fine particles is suppressed in the dispersion liquid. ..
The volume average particle size can be measured using a laser diffraction / scattering type particle size distribution measuring device LA-920 (manufactured by HORIBA).
The higher the concentration of inorganic fine particles in the surface layer, the higher the abrasion resistance, which is good. However, if it is too high, the residual potential increases and the write light transmittance of the outermost surface layer decreases, which may cause side effects. .. Therefore, the concentration of the inorganic fine particles is approximately 50% by weight or less, preferably 30% by weight or less, based on the total solid content. The lower limit is usually 5% by weight.

The image forming apparatus of the present invention is formed on the surface of an image carrier, a charging means for charging the surface of the image carrier, an exposure means for writing an electrostatic latent image on the surface of the charged image carrier, and an image carrier. It is provided with a developing means for visualizing a latent image with toner and a transfer means for transferring a toner image on the surface of the image carrier to a transfer target.
Further, the image forming method of the present invention includes a charging step of charging the surface of the image carrier, an exposure step of writing an electrostatic latent image on the surface of the charged image carrier, and a latent image formed on the surface of the image carrier. A development step of visualizing with a toner and a transfer step of transferring the toner image on the surface of the image carrier to the transferee are sequentially provided.
Hereinafter, the image forming apparatus of FIG. 1 will be described as an example as an embodiment of the apparatus and method of the present invention.

In FIG. 1, the image forming apparatus 100A includes a photoconductor drum 10 as an electrostatic latent image carrier, a charging roller 20 as a charging means, an exposure device (not shown) as an exposure means, and development as a developing means. It has a vessel 45 (K, Y, M, C), an intermediate transfer member 50, a cleaning device 60 having a cleaning blade as a cleaning means, and a static eliminating lamp 70 as a static eliminating means.

The intermediate transfer body 50 is an endless belt, is stretched by three rollers 51 arranged inside the intermediate transfer body 50, and can move in the direction of the arrow. A part of the three rollers 51 also functions as a transfer bias roller capable of applying a predetermined transfer bias (primary transfer bias) to the intermediate transfer body 50.

Further, a cleaning device 90 having a cleaning blade is arranged in the vicinity of the intermediate transfer body 50. Further, a transfer roller 80 as a transfer means capable of applying a transfer bias for transferring (secondary transfer) the toner image to the recording paper 95 is arranged so as to face the intermediate transfer body 50.
Further, around the intermediate transfer body 50, a corona charger 52 for applying an electric charge to the toner image on the intermediate transfer body 50 is provided at the contact portion between the photoconductor drum 10 and the intermediate transfer body 50 and the intermediate transfer body 50. It is arranged between the contact portion of the recording paper 95 and the contact portion of the recording paper 95.

The developer 45 for each color of black (K), yellow (Y), magenta (M), and cyan (C) includes a developer accommodating portion 42 (K, Y, M, C), a developer supply roller 43, and a developer supply roller 43. A developing roller 44 is provided.

In the image forming apparatus 100A, the photoconductor drum 10 is uniformly charged by the charging roller 20, and then the exposure light L is exposed on the photoconductor drum 10 in an image manner by an exposure apparatus (not shown) to form an electrostatic latent image. To form. Next, the electrostatic latent image formed on the photoconductor drum 10 is developed by supplying a developer from the developer 45 to form a toner image, and then the toner image is formed by the transfer bias applied from the roller 51. Is transferred (primary transfer) onto the intermediate transfer member 50. Further, the toner image on the intermediate transfer body 50 is charged by the corona charger 52 and then transferred (secondary transfer) on the recording paper 95. The toner remaining on the photoconductor drum 10 is removed by the cleaning device 60, and the photoconductor drum 10 is once statically eliminated by the static elimination lamp 70.

FIG. 2 shows another example of the image forming apparatus of the present invention. The image forming apparatus 100B is a tandem type color image forming apparatus, and includes a copying apparatus main body 150, a paper feed table 200, a scanner 300, and an automatic document transporting apparatus (ADF) 400.

The copying apparatus main body 150 is provided with an endless belt-shaped intermediate transfer body 50 at the center. The intermediate transfer body 50 is stretched on the support rollers 14, 15 and 16 and can rotate in the direction of the arrow.
A cleaning device 17 for removing the toner remaining on the intermediate transfer body 50 is arranged in the vicinity of the support roller 15. Further, on the intermediate transfer body 50 stretched by the support roller 14 and the support roller 15, four image forming means 18 of yellow, cyan, magenta, and black are juxtaposed so as to face each other along the transport direction. A tandem type developer 120 is arranged.

As shown in FIG. 3, the image forming means 18 of each color blackens the photoconductor drum 10, the charging roller 60 that uniformly charges the photoconductor drum 10, and the electrostatic latent image formed on the photoconductor drum 10. A developer 70 that forms a toner image by developing with a developer of each color of (K), yellow (Y), magenta (M), and cyan (C), and a toner image of each color are transferred onto the intermediate transfer body 50. A transfer roller 62 for this purpose, a cleaning device 63, and a static elimination lamp 64 are provided.

Further, in the image forming apparatus of FIG. 2, an exposure apparatus 21 is arranged in the vicinity of the tandem type developer 120. The exposure apparatus exposes the exposure light on the photoconductor drum 10 to form an electrostatic latent image.
Further, the secondary transfer device 22 is arranged on the side of the intermediate transfer body 50 opposite to the side on which the tandem developer 120 is arranged. The secondary transfer device 22 includes a secondary transfer belt 24 which is an endless belt stretched on a pair of rollers 23, and the recording paper conveyed on the secondary transfer belt 24 and the intermediate transfer body 50 can come into contact with each other. It has become.

A fixing device 25 is arranged in the vicinity of the secondary transfer device 22. The fixing device 25 has a fixing belt 26 which is an endless belt and a pressure roller 27 which is pressed and arranged by the fixing belt 26.
Further, in the vicinity of the secondary transfer device 22 and the fixing device 25, a reversing device 28 that reverses the recording paper in order to form an image on both sides of the recording paper is arranged.

Next, the formation (color copy) of a full-color image in the image forming apparatus 100B will be described. First, the document is set on the platen 130 of the automatic document transfer device (ADF) 400, or the document is set on the contact glass 32 of the scanner 300 by opening the automatic document transfer device 400, and the automatic document transfer device 400 is set. close. Next, when the start switch (not shown) is pressed, when the original is set in the automatic document conveying device 400, the original is conveyed and moved onto the contact glass 32, and then the original is placed on the contact glass 32. When set, the scanner 300 is immediately driven, and the first traveling body 33 and the second traveling body 34 travel. At this time, the light from the light source is irradiated by the first traveling body 33, the reflected light from the document surface is reflected by the mirror in the second traveling body 34, and is received by the reading sensor 36 through the imaging lens 35. .. As a result, a color original (color image) is read, and image information of each color of black, yellow, magenta, and cyan is obtained.

Further, after the electrostatic latent image of each color is formed on the photoconductor drum 10 based on the image information of each color obtained by the exposure apparatus, the electrostatic latent image of each color is supplied from the developer 120 of each color. It is developed with a developing agent to form a toner image of each color. The formed toner images of each color are sequentially superimposed and transferred (primary transfer) on the intermediate transfer body 50 which is rotationally moved by the support rollers 14, 15 and 16, and a composite toner image is formed on the intermediate transfer body 50. ..

In the paper feed table 200, one of the paper feed rollers 142 is selectively rotated, and the recording paper is fed out from one of the paper feed cassettes 144 provided in the paper bank 143 in multiple stages, and the paper is separated one by one by the separation roller 145. It is sent out to the paper feed path 146, conveyed by the transfer roller 147, guided to the paper feed path 148 in the copying machine main body 150, and abutted against the registration roller 49 to be stopped. Alternatively, the recording paper on the manual feed tray 54 is fed out, separated one by one by the separation roller 58, put into the manual feed feed path 53, and abutted against the resist roller 49 to stop. Although the resist roller 49 is generally used on the ground, it may be used in a state where a bias is applied in order to remove paper dust from the recording paper.

Then, the resist roller 49 is rotated in time with the composite toner image formed on the intermediate transfer body 50, the recording paper is sent out between the intermediate transfer body 50 and the secondary transfer device 22, and the composite toner image is printed on the recording paper. Transfer to (secondary transfer).

The recording paper on which the composite toner image is transferred is conveyed by the secondary transfer device 22 and sent out to the fixing device 25. Then, in the fixing device 25, the composite toner image is fixed on the recording paper by being heated and pressed by the fixing belt 26 and the pressure roller 27. After that, the recording paper is switched by the switching claw 55, discharged by the discharge roller 56, and stacked on the paper discharge tray 57.
Alternatively, the image is switched by the switching claw 55, inverted by the reversing device 28, guided to the transfer position again, an image is formed on the back surface, and then the image is discharged by the discharge roller 56 and stacked on the paper discharge tray 57.
The toner remaining on the intermediate transfer body 50 after the composite toner image is transferred is removed by the cleaning device 17.

FIG. 4 shows an example of the process cartridge.
The image forming apparatus according to the present invention may be configured to be detachably provided with a process cartridge.
The process cartridge 110 includes a photoconductor drum 10, a corona charger 52, a developing device 40, a transfer roller 80, and a cleaning device 90.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the examples and comparative examples exemplified here. The part in the example represents a mass part unless otherwise specified.

[Manufacturing of toner]
A specific example of producing the toner used for the evaluation will be described. The toner used in the present invention is not limited to these examples.

~ Synthesis of ketimin ~
170 parts of isophorone diamine and 75 parts of methyl ethyl ketone were charged in a reaction vessel in which a stirring rod and a thermometer were set, and the reaction was carried out at 50 ° C. for 5 hours to obtain [ketimine compound]. The amine value of [Ketimin compound] was 418.

~ Synthesis of crystalline polyester resin A ~
In a reaction vessel set with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, 202 parts of sebacic acid and 106 parts of 1,6-hexanediol were charged, and 10 parts by mass of titanium tetraisopropoxide as a polycondensation catalyst was added. It was added in divided doses. Next, after reacting at 180 ° C. for 10 hours, the temperature was raised to 200 ° C. and the reaction was carried out for 3 hours. Further, the reaction was carried out under a reduced pressure of 8.3 kPa for 2 hours to obtain [Crystallinity Polyester A]. [Crystallinity polyester A] had a melting point of 67 ° C. and a weight average molecular weight of 25,000.

~ Synthesis of crystalline polyester resin B ~
271 parts by mass of tetradecanedioic acid and 118 parts by mass of 1,6-hexanediol were charged in a reaction vessel in which a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple were set, and 0.8 mass of titanium tetraisopropoxide as a polycondensation catalyst. The portions were added in 10 portions. Next, after reacting at 235 ° C. for 5 hours, the temperature was raised to 200 ° C. and the reaction was carried out for 3 hours. Further, the reaction was carried out under a reduced pressure of 13.3 kPa for 1 hour to obtain [Crystallinity Polyester B]. [Crystallinity polyester B] had a melting point of 64 ° C. and a weight average molecular weight of 15,000.

~ Synthesis of amorphous polyester resin A ~
229 parts of bisphenol A ethylene oxide side 2 mol adduct, 529 parts of bisphenol A propylene oxide 3 mol adduct, terephthalic acid in a 5 liter four-necked flask equipped with a nitrogen introduction tube, dehydration tube, stirrer and thermocouple. 208 parts, 46 parts of adipic acid and 2 parts of dibutyltin oxide were added, reacted at 230 ° C. for 7 hours at normal pressure, and further reacted at a reduced pressure of 10 to 15 mmHg for 4 hours, and then 44 parts of trimellitic anhydride was placed in a reaction vessel. The mixture was charged and reacted at 180 ° C. and normal pressure for 2 hours to obtain [amorphous polyester A]. [Amorphous polyester] had a weight average molecular weight (Mw) of 5,800 and a glass transition temperature of 55 ° C.

~ Synthesis of amorphous polyester resin B ~
360 parts of bisphenol A propylene oxide 2 mol adduct, 80 parts of terephthalic acid, 55 parts of fumaric acid, and titanium tetraiso in a 5 liter four-necked flask equipped with a nitrogen introduction tube, dehydration tube, stirrer and thermocouple. Two parts of propoxide were added, reacted at 200 ° C. for 10 hours at normal pressure, further reacted under a reduced pressure of 13.3 kPa (100 mmHg), and taken out when the softening point reached 104 ° C. to remove the amorphous polyester resin B. Obtained.

~ Synthesis of polyester prepolymer A ~
682 parts of bisphenol A ethylene oxide 2 mol adduct, 81 parts of bisphenol A propylene oxide 2 mol adduct, 283 parts of terephthalic acid, 22 parts of trimellitic anhydride in a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen rod introduction tube. A part and 2 parts of dibutyltin oxide were added, and the reaction was carried out at 230 ° C. for 8 hours at normal pressure, and further reacted at a reduced pressure of 10 to 15 mmHg for 5 hours to obtain [Intermediate Polyester A]. [Intermediate polyester A] had a weight average molecular weight of 9,500, a glass transition temperature of 55 ° C., an acid value of 0.5, and a hydroxyl value of 51.
Next, 410 parts of [Intermediate Polyester A], 89 parts of isophorone diisocyanate, and 500 parts of ethyl acetate were placed in a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, and reacted at 100 ° C. for 5 hours. Polymer A] was obtained.

~ Synthesis of polyester prepolymer B ~
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 1430 parts of 3-methyl-1,5-pentanediol, 1125 parts of adipic acid, 38 parts of trimellitic anhydride and 2.6 parts of titanium tetraisopropoxide. The temperature was raised to 200 ° C. in about 4 hours at normal pressure, further raised to 230 ° C. in 2 hours, reacted until water stopped flowing out, and then reacted under reduced pressure of 10 to 15 mmHg for 5 hours. [Intermediate polyester B] was obtained.
Next, 271 parts of [Intermediate polyester B], 91 parts of isophorone diisocyanate, and 362 parts of ethyl acetate were placed in a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, and reacted at 100 ° C. for 5 hours. Prepolymer B] was obtained.
[Polyester prepolymer] was charged into a reaction vessel in which a heating device, a stirrer and a nitrogen introduction tube were set, and the mixture was stirred, and then ketimine was added dropwise. At this time, the molar ratio of the amino group to the isocyanate group was set to 1. Next, after stirring at 45 ° C. for 10 hours, the mixture was dried under reduced pressure at 50 ° C. until the remaining amount of ethyl acetate became 100 ppm or less to obtain [amorphous polyester resin B']. [Amorphous polyester B'] had a glass transition temperature of −55 ° C. and a weight average molecular weight of 130000.

The melting point, glass transition temperature, and weight average molecular weight were determined as follows.
<Melting point and glass transition temperature>
The melting point and the glass transition temperature were measured using a differential scanning calorimeter Q-200 (manufactured by TA Instruments). Specifically, after about 5.0 mg of the target sample was placed in a sample container made of aluminum, the sample container was placed on a holder unit and set in an electric furnace. Next, the temperature was raised from −80 ° C. to 150 ° C. at a heating rate of 10 ° C./min under a nitrogen atmosphere.
From the obtained DSC curve, the glass transition temperature of the target sample was determined using the analysis program in the differential scanning calorimeter.
Further, from the obtained DSC curve, the endothermic peak top temperature of the target sample was determined as the melting point by using the analysis program in the differential scanning calorimeter.

<Weight average molecular weight>
The weight average molecular weight was measured using a GPC measuring device HLC-8220 GPC (manufactured by Tosoh Corporation) and a column TSKgel SuperHZM-H 15 cm triplet (manufactured by Tosoh Corporation). Specifically, the column was stabilized in a heat chamber at 40 ° C. Next, tetrahydrofuran (THF) was flowed through the column at a flow rate of 1 mL / min, and 50 to 200 μL of a THF solution of 0.05 to 0.6% by mass of the sample was injected, and the weight average molecular weight of the sample was measured. At this time, the weight average molecular weight of the sample was calculated from the relationship between the logarithmic value of the calibration curve prepared using several types of monodisperse polystyrene standard samples and the number of counts.
As standard polystyrene samples, the weight average molecular weights are 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , and so on. Samples of 3.9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , and 4.48 × 10 ⁶ (manufactured by Polystyrene Chemical or Tosoh) were used.
An RI (refractive index) detector was used as the detector.

-Manufacture of fine particles A containing strontium titanate as the main component-
After deironing and bleaching the metatitanic acid obtained by the sulfuric acid method, an aqueous sodium hydroxide solution was added to adjust the pH to 9.0, desulfurization was performed, and then neutralized to pH 5.8 with hydrochloric acid and washed with filtered water. Obtained a washed cake. Water was added to the washed cake to make a slurry of 2 mol / L as TiO ₂ , and then hydrochloric acid was added to adjust the pH to 1.4, and a gelatinizing treatment was performed. 1.50 mol of this metatitanium acid was collected as TiO ₂ and charged into a 3 L reaction vessel. A strontium chloride solution of 1.73 mol and a lanthanum chloride solution of 0.26 mol were added to adjust the TiO ₂ concentration to 0.70 mol / L. Next, after heating to 90 ° C. with stirring, 438 mL of a 10N sodium hydroxide aqueous solution was added over 2 hours, and then stirring was continued at 95 ° C. for 1 hour to complete the reaction.

The reaction-terminated slurry was cooled to 50 ° C., hydrochloric acid was added until the pH reached 5.0, and stirring was continued for 1 hour. After decantation washing of the obtained precipitate, adjust the temperature to 50 ° C., add hydrochloric acid to adjust the pH to 2.5, and add 10.0 wt% i-butyltrimethoxysilane (surface treatment agent) to the solid content. After continuing stirring and holding for 6 hours, 3.0 wt% of trifluoropropyltrimethoxysilane (surface treatment agent) was added and stirring and holding was continued for 14 hours. Next, a sodium hydroxide solution was added to adjust the pH to 6.5, and the cake was kept stirred for 1 hour. Then, the cake obtained by filtration and washing was dried in the air at 120 ° C. for 10 hours, and strontium titanate was used as a main component. Fine particles A to be produced were obtained. The (Sr + La) / Ti molar ratio of the fine particles A containing strontium titanate as a main component was 0.88, and the number average primary particle size was 40 nm.

-Manufacture of fine particles BG containing strontium titanate as a main component-
Fine particles B to G containing strontium titanate as a main component were obtained in the same manner as the fine particles A containing strontium titanate as a main component except that the reaction conditions are shown in Table 1.

The above (Sr + La) / Ti molar ratio and the number average primary particle size were determined as follows.
<(Sr + La) / Ti molar ratio>
The count value of each element was measured using a fluorescent X-ray analyzer XRF-1700 manufactured by Shimadzu Corporation, and calculated by the Fundamental Parameter method (JIS K 0119: 2008).

<Number average primary particle size>
An SEM image of fine particles containing strontium titanate as a main component was acquired using a field emission scanning electron microscope SU8230 (manufactured by Hitachi High-Tech), and the number average particle size was measured by image analysis. First, fine particles containing strontium titanate as a main component were dispersed in tetrahydrofuran, and then the solvent was removed on the substrate and dried. This sample was observed by the above SEM to obtain an image, and the maximum length of the primary particle was measured for each particle. The average value of 50 particles was calculated and used as the number average particle diameter. An example of SEM measurement conditions is shown.

[SEM measurement conditions]
Acceleration voltage: 2.0kV
WD (Working Distance): 5.0 mm
Observation magnification: 100,000 times

~ Preparation of masterbatch (MB) ~
Add 1200 parts of water, carbon black (manufactured by Printex 35 Dexa) [DBP oil absorption = 42 ml / 100 mg, pH = 9.5] 540 parts, [amorphous polyester resin A] 1200 parts, and add Henshell mixer (manufactured by Mitsui Mining Co., Ltd.). The mixture was kneaded at 150 ° C. for 30 minutes using two rolls, rolled and cooled, and pulverized with a palpelizer to obtain a [master batch].

-Creation of amorphous polyester resin / pigment / WAX dispersion A1-
In a container in which a stirring rod and a thermometer are set, 378 parts of [amorphous polyester resin A], 110 parts of carnauba WAX, 22 parts of CCA (metal salicylate complex E-84: Orient Chemical Industry), and 947 parts of ethyl acetate are charged and stirred. The temperature was raised to 80 ° C., kept at 80 ° C. for 5 hours, and then cooled to 30 ° C. at 1 o'clock. Next, 500 parts of [master batch] and 500 parts of ethyl acetate were placed in a container and mixed for 1 hour to obtain a [raw material solution].
[Raw material solution] Transfer 1324 parts to a container and fill 80% by volume of liquid feeding speed 1 kg / hr, disk peripheral speed 6 m / sec, 0.5 mm zirconia beads using a bead mill (Ultra Viscomill, manufactured by Imex). Carbon black and wax were dispersed under the condition of 3 passes. Next, 900 parts of a 65% ethyl acetate solution of [amorphous polyester resin A] was added, and one pass was performed with a bead mill under the above conditions to obtain [pigment / wax dispersion A1]. The solid content concentration (130 ° C., 30 minutes) of [Pigment / WAX dispersion A1] was 55%.

-Creation of amorphous polyester resin / pigment / WAX dispersion A2-
In a container in which a stirring rod and a thermometer are set, 378 parts of [amorphous polyester resin A], 110 parts of carnauba WAX, 22 parts of CCA (metal salicylate complex E-84: Orient Chemical Industry), and 947 parts of ethyl acetate are charged and stirred. The temperature was raised to 80 ° C., kept at 80 ° C. for 5 hours, and then cooled to 30 ° C. at 1 o'clock. Next, 500 parts of [master batch] and 500 parts of ethyl acetate were placed in a container and mixed for 1 hour to obtain a [raw material solution].
[Raw material solution] Transfer 1324 parts to a container and fill 80% by volume of liquid feeding speed 1 kg / hr, disk peripheral speed 6 m / sec, 0.5 mm zirconia beads using a bead mill (Ultra Viscomill, manufactured by Imex). Carbon black and wax were dispersed under the condition of 3 passes. Next, 1042.3 parts of a 65% ethyl acetate solution of [amorphous polyester resin A] was added, and one pass was performed with a bead mill under the above conditions to obtain [pigment / wax dispersion A2]. The solid content concentration (130 ° C., 30 minutes) of [Pigment / WAX dispersion A2] was 50%.

~ Preparation of crystalline polyester dispersion A ~
100 parts of [Crystallinity Polyester Resin A] and 400 parts of ethyl acetate were placed in a metal 2L container, dissolved by heating at 75 ° C., and then rapidly cooled in an ice water bath at a rate of 27 ° C./min. 500 ml of glass beads (3 mmφ) were added thereto, and the mixture was pulverized with a batch type sand mill device (manufactured by Campe Hapio) for 10 hours to obtain [Crystallinity Polyester Dispersion A].

-Creation of crystalline polyester dispersion B-
[Crystalolic polyester resin B] 100 parts by mass was crushed with "Randelmill type: RM" (manufactured by Tokuju Kosakusho Co., Ltd.) and mixed with 638 parts by mass of a 0.26% by mass concentration sodium lauryl sulfate solution prepared in advance. Using an ultrasonic homogenizer "US-150T" (manufactured by Nippon Seiki Seisakusho) with stirring, ultrasonically disperse at V-LEVEL, 300 μA for 30 minutes to prepare a crystalline polyester dispersion B having a volume-based median diameter of 200 nm. did.

-Creation of organic fine particle dispersion-
In a reaction vessel with a stirring rod and a thermometer set, 683 parts of water, 11 parts of sodium salt of ethylene methacrylate adduct sulfate (Eleminol RS-30: manufactured by Sanyo Kasei Kogyo), 138 parts of styrene, 138 parts of methacrylic acid, When 1 part of ammonium persulfate was charged and stirred at 400 rpm for 15 minutes, a white emulsion was obtained. The temperature was raised to 75 ° C. in the system by heating, and the reaction was carried out for 5 hours. Further, 30 parts of 1% ammonium persulfate aqueous solution was added and aged at 75 ° C. for 5 hours to obtain an aqueous dispersion of a vinyl resin (copolymer of sodium salt of styrene-methacrylic acid-methacrylic acid ethylene oxide adduct sulfate ester) [fine particles]. Dispersion] was obtained. The volume average particle diameter of the [fine particle dispersion] measured by LA-920 was 0.14 μm. A part of the [fine particle dispersion] was dried to isolate the resin component.

-Creation of styrene acrylic resin / WAX dispersion A-
(1) First-stage polymerization In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device, a surfactant solution prepared by dissolving 8 parts by mass of sodium dodecyl sulfate in 3000 parts by mass of ion-exchanged water was prepared. The internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. After raising the temperature, a solution prepared by dissolving 10 parts by mass of potassium persulfate (KPS) in 200 parts by mass of ion-exchanged water was added to the above-mentioned surfactant solution, the liquid temperature was adjusted to 80 ° C. again, and then the following compound was contained. The polymerizable monomer mixed solution was added dropwise over 1 hour.

Styrene 480 parts by mass n-Butyl acrylate 250 parts by mass Methacrylic acid 68 parts by mass n-octyl-3-mercaptopropionate 16 parts by mass

After dropping the above-mentioned polymerizable monomer mixed solution, this system is heated and stirred at 80 ° C. for 2 hours to carry out polymerization (first-stage polymerization), and "resin particles" containing "resin particles [1h]". A dispersion [1H] ”was prepared.

(2) Second-stage polymerization In a flask equipped with a stirrer, the following compound was added and heated to 90 ° C. to dissolve it to prepare a mixed solution containing a polymerizable monomer and a release agent. ..

245 parts by mass of styrene n-butyl acrylate 120 parts by mass n-octyl-3-mercaptopropionate 1.5 parts by mass Carnauba wax 110 parts by mass

On the other hand, a surfactant solution prepared by dissolving 7 parts by mass of polyoxyethylene-2-dodecyl ether sodium sulfate in 800 parts by mass of ion-exchanged water was heated to 98 ° C. To this surfactant solution, an amount of the resin particle dispersion 1H having an amount of the "resin particles 1h" in terms of solid content of 260 parts by mass, and a mixed solution containing the polymerizable monomer and a release agent are added. did. After their addition, a dispersion containing emulsified particles was prepared by performing a mixing and dispersing treatment for 1 hour using a mechanical disperser "Clearmix" (manufactured by M-Technique) having a circulation path.

Next, a solution prepared by dissolving 6 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water was added to this dispersion, and this system was heated and stirred at 82 ° C. for 1 hour to polymerize (second stage polymerization). To prepare a "resin particle dispersion solution [1HM]" containing "resin particles [1 hm]".

(3) Third-stage polymerization An initiator solution prepared by dissolving 11 parts by mass of potassium persulfate in 400 parts by mass of ion-exchanged water was added to the above-mentioned "resin particle dispersion liquid [1HM]" to bring the liquid temperature to 80 ° C. Then, a polymerizable monomer mixed solution containing the following compound was added dropwise over 1 hour.

Styrene 435 parts by mass n-Butyl acrylate 130 parts by mass Methacrylic acid 33 parts by mass n-octyl-3-mercaptopropionate 8 parts by mass

After the completion of dropping the above-mentioned polymerizable monomer mixed solution, polymerization (third-stage polymerization) was carried out by heating and stirring for 2 hours, and then the mixture was cooled to 28 ° C. and contained "resin particles [a]". Styrene acrylic resin / WAX dispersion A ”was prepared. The particle size of the "resin particles [a]" contained in the above "styrene acrylic resin / WAX dispersion A" was measured using an electrophoretic light scattering photometer "ELS-800 (manufactured by Otsuka Electronics Co., Ltd.)". The volume-based median diameter was 150 nm. Moreover, when the glass transition temperature was measured by a known method, it was 45 ° C. The weight average molecular weight of the resin constituting the resin particles [a] was 32,000.

~ Creation of amorphous polyester resin dispersion B ~
100 parts by mass of amorphous polyester resin B is crushed with "Randelmill type: RM" (manufactured by Tokuju Kosakusho Co., Ltd.), mixed with 638 parts by mass of a 0.26% by mass concentration sodium lauryl sulfate solution prepared in advance, and stirred. While using an ultrasonic homogenizer "US-150T" (manufactured by Nippon Seiki Seisakusho), ultrasonically disperse at V-LEVEL, 300 μA for 30 minutes to prepare an amorphous polyester resin dispersion B having a mass-based median diameter of 250 nm. did.

~ Preparation of pigment dispersion liquid ~
While stirring a solution prepared by dissolving 90 parts by mass of sodium dodecyl sulfate in 1600 parts by mass of ion-exchanged water, C.I. I. Pigment Blue 15: 3 (manufactured by Toyo Ink Co., Ltd.) 420 parts by mass was gradually added. Next, a "pigment dispersion liquid" was prepared by performing a dispersion treatment using a stirring device "Clearmix (manufactured by M-Technique Co., Ltd.)".

~ Preparation of WAX dispersion ~
After adding 50 parts by mass of paraffin wax (melting point: 73 ° C.), 2 parts by mass of sodium n-dodecyl sulfate, and 200 parts by mass of ion-exchanged water, heat to 120 ° C. and mix with Ultratarax T50 manufactured by IKA. After the dispersion, the dispersion treatment was carried out with a pressure discharge type homogenizer to obtain a WAX dispersion having a volume average particle diameter of 200 nm and a solid content of 20%.

(Manufacturing of toner 1)
~ Adjustment of water phase ~
990 parts of water, 83 parts of [fine particle dispersion], 37 parts of 48.5% aqueous solution of sodium dodecyldiphenyl ether disulfonate (eleminol MON-7: manufactured by Sanyo Chemical Industries, Ltd.), 90 parts of ethyl acetate are mixed and stirred to make a milky white liquid. Obtained. This is referred to as [water phase].

~ Emulsification / solvent removal ~
Put 500 parts of [Amorphous polyester resin / pigment / WAX dispersion A1], 96 parts of [Prepolymer A], 150 parts of [Crystalline polyester dispersion A], and 4.0 parts of [Ketimin compound] in a container. , TK homomixer (manufactured by Special Machinery Co., Ltd.) at 5,000 rpm for 1 minute, then add 1200 parts of [aqueous phase] to the container, and mix with TK homomixer at 8,000 rpm for 60 seconds [emulsification slurry]. ] Was obtained.
[Emulsified slurry] was put into a container in which a stirrer and a thermometer were set, solvent was removed at 30 ° C. for 8 hours, and then aged at 45 ° C. for 4 hours to obtain a [dispersed slurry].

~ Washing / drying ~
After filtering 100 parts of [dispersed slurry] under reduced pressure,
(1): 100 parts of ion-exchanged water was added to the filtered cake, mixed with a TK homomixer (rotation speed 12,000 rpm for 10 minutes), and then filtered.
(2): 100 parts of a 10% aqueous sodium hydroxide solution was added to the filtered cake of (1), mixed with a TK homomixer (rotation speed 12,000 rpm for 30 minutes), and then filtered under reduced pressure.
(3): 100 parts of 10% hydrochloric acid was added to the filtered cake of (2), mixed with a TK homomixer (rotation speed 12,000 rpm for 10 minutes), and then filtered.
(4): 300 parts of ion-exchanged water was added to the filtered cake of (3), mixed with a TK homomixer (rotation speed 12,000 rpm for 10 minutes), and then filtered twice to obtain a [filtered cake]. ..
The [filtered cake] was dried at 45 ° C. for 48 hours in a circulation dryer to obtain sieve toner matrix particles 1 with a mesh having an opening of 75 μm.

~ External processing ~
Large particle size hydrophobic silica UFP-35 (average primary particle size 78 nm, manufactured by Denki Kagaku Co., Ltd., silica A) is added to 100 parts of the toner matrix particle 1 and 2.0 parts, small particle size hydrophobic silica RX-50 ( Average primary particle size, 40 nm, manufactured by Nippon Aerosil Co., Ltd., silica B) is mixed with 1.6 parts, and 0.6 parts of fine particles A containing strontium titanate as the main component are mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.). Then, it was passed through a sieve having a mesh size of 500 mesh to obtain [Toner 1].

(Manufacturing of toners 2 to 18)
In the emulsification / removal of the toner 1, the same operation was carried out except that the number of parts for preparing the oil phase and the number of parts for the external additive were changed as shown in Tables 2 and 3, to obtain toners 2 to 18. The titanium oxide ST-550 in the table is hydrophobic titanium oxide ST-550 (average primary particle size 40 nm, manufactured by Titan Kogyo), and the alumina is alumina Alu C 805 (average primary particle size 13 nm, manufactured by Nippon Aerosil). is there.

(Manufacturing of toner 19)
The following compounds were put into a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device.

"Styrene acrylic resin / WAX dispersion A" 300 parts by mass (solid content equivalent)
Ion-exchanged water 1400 parts by mass Pigment dispersion 24.5 parts by mass (solid content equivalent)

Next, a solution prepared by further dissolving 3 parts by mass of sodium polyoxyethylene-2-dodecyl sulfate in 120 parts by mass of ion-exchanged water was added to the above reaction vessel to bring the liquid temperature to 30 ° C., and then 5 mol / liter. The pH was adjusted to 10 by adding an aqueous sodium hydroxide solution.

Next, an aqueous solution prepared by dissolving 35 parts by mass of magnesium chloride hexahydrate in 35 parts by mass of ion-exchanged water was added at 30 ° C. for 10 minutes under a stirring state, held for 3 minutes, and then the temperature was raised. It started. The temperature was raised to 90 ° C. over 60 minutes, and the particles were aggregated and fused while being held at 90 ° C. In this state, the particle size of the particles growing in the reaction vessel was measured using "Multisizer 3 (manufactured by Beckman Coulter)", and when the volume-based median diameter reached 6.5 μm, 150 parts by mass of sodium chloride was measured. Was added to 600 parts by mass of ion-exchanged water to stop the growth of particles. Further, as an aging treatment, the liquid temperature was set to 98 ° C., and the mixture was heated and stirred, and the fusion of the particles was promoted until the average circularity became 0.965 as measured by "FPIA-2100 (manufactured by Sysmex Corporation)".

Then, the liquid temperature was cooled to 30 ° C., the pH of the liquid was adjusted to 2 using hydrochloric acid, and stirring was stopped. In this way, a "toner matrix particle dispersion liquid [B1]" was prepared.

The "toner matrix particle dispersion [B1]" prepared through the above steps is solid-liquid separated by a basket-type centrifuge "MARKIII model number 60 x 40 (manufactured by Matsumoto Machinery Co., Ltd.)", and "toner matrix particles [b1]" are separated. ] ”Wet cake was formed.

This wet cake is washed with the basket-type centrifuge with ion-exchanged water at 45 ° C. until the electrical conductivity of the filtrate reaches 5 μS / cm, and then “Flash Jet Dryer (manufactured by Seishin Enterprise Co., Ltd.)”. A cyan-colored "toner matrix particle [b1]" was prepared by carrying out a drying treatment until the water content became 0.5% by mass.
Toner 19 was prepared by changing the number of copies of the external additive with respect to the "toner matrix particles [b1]" as shown in Table 3.

(Manufacturing of toner 20)
In a reaction vessel equipped with a stirrer, temperature sensor and cooling tube, 250 parts by mass of amorphous polyester resin dispersion B in terms of solid content, 47 parts by mass of crystalline polyester dispersion B in terms of solid content, WAX dispersion 18 parts by mass in terms of solid content and 2000 parts by mass of ion-exchanged water were added, and then a 5 mol / liter aqueous sodium hydroxide solution was added to adjust the pH to 10 at 30 ° C. Then, 26 parts by mass of the pigment dispersion was added in terms of solid content. Next, an aqueous solution prepared by dissolving 60 parts by mass of magnesium chloride in 60 parts by mass of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. Then, after leaving it for 3 minutes, the temperature was started, the temperature of this system was raised to 80 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 80 ° C. In this state, the particle size of the associated particles was measured with "Multisizer 3" (manufactured by Beckman Coulter), and when the volume-based median diameter reached 6.5 μm, 190 parts by mass of sodium chloride was added to ion-exchanged water. A dissolved aqueous solution was added to 760 parts by mass to stop particle growth. Further, the temperature is raised and the particles are heated and stirred at 90 ° C. to promote the fusion of the particles, and the average circularity of the toner is measured using the measuring device "FPIA-2100" (manufactured by Sysmex) (HPF detection). When the measured average circularity reached 0.955, the mixture was cooled to 30 ° C. to prepare a dispersion liquid [B2] of toner population particles.
The dispersion liquid [B2] of the toner matrix particles is solid-liquid separated by a centrifuge to form a wet cake of the toner matrix particles [b2], and the wet cake is subjected to a filtrate having an electrical conductivity of 5 μS in the centrifuge. Wash with ion-exchanged water at 35 ° C until it reaches / cm, then transfer to a "flash jet dryer" (manufactured by Seishin Enterprise Co., Ltd.) and dry until the water content reaches 0.5% by mass. b2] was created.
The toner 20 was prepared by changing the number of copies of the external additive with respect to the "toner matrix particles [b2]" as shown in Table 3.

The average number of toners, the particle size Dn, the average value X of the amount of deformation due to micro-pressing, the coverage of the external additive, and the radius R were determined as follows.

<Dn>
Toner Dn was measured using a Coulter Multi-Sizar II (manufactured by Beckman Coulter). First, 0.1 mL to 5 mL of polyoxyethylene alkyl ether was added as a dispersant to 100 mL to 150 mL of the aqueous electrolyte solution. Here, the electrolyte aqueous solution was prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride, and ISOTON-II (manufactured by Coulter) was used. Further, 2 mg to 20 mg of toner was added. An aqueous electrolyte solution in which the toner was suspended was dispersed for about 1 to 3 minutes using an ultrasonic disperser, and then the particle size and number of toners were measured using a 100 μm aperture to determine Dn.
The channels are 2.00 μm or more and less than 2.52 μm; 2.52 μm or more and less than 3.17 μm; 3.17 μm or more and less than 4.00 μm; 4.00 μm or more and less than 5.04 μm; 5.04 μm or more and less than 6.35 μm; 6 .35 μm or more and less than 8.00 μm; 8.00 μm or more and less than 10.08 μm; 10.08 μm or more and less than 12.70 μm; 12.70 μm or more and less than 16.00 μm; 16.00 μm or more and less than 20.20 μm; 20.20 μm or more and 25. Less than 40 μm; 25.40 μm or more and less than 32.00 μm; 13 channels of 32.00 μm or more and less than 40.30 μm were used, and particles having a particle size of 2.00 μm or more and less than 40.30 μm were targeted.

<X>
The amount of toner deformation due to minute indentation was measured using an ultra-fine indentation hardness tester ENT-2100 (manufactured by Elionix Inc.).
The measurement method will be described below.
In this device, a load-displacement curve can be obtained by measuring the load and displacement on the indenter when the indenter is pushed into the sample. From this curve, the amount of toner deformation can be measured. The flow of the indentation test is as follows. When the measurement was started, the indenter was pushed in at a constant load speed, and the maximum load was reached. A micro-indentation test was performed under the following measurement conditions.
Indenter: 20 μm × 20 μm planar indenter Measurement environment: 32 ° C, 40% RH
Load speed: 3.0 × ^10-5 N / sec
Maximum load: 3.0 x 10 ^-4 N
Number of toners to measure: 30
Specifically, toner was placed on a glass substrate, and by air blowing, a large amount of toner was present as one particle without aggregation. The toner to be measured was selected while confirming the existence of one particle by the microscope attached to the apparatus. At that time, the major axis and the minor axis of the toner were measured by the software attached to the apparatus, and only the toner having the major axis of Dn ± 0.3 μm was selected in order to prevent the particle size of the measured toner from being biased. If the toner adheres to the indenter after the micro-indentation test, wipe it off with a soft cloth or the like, and then confirm from the load-displacement curve when the indenter is pressed against the substrate that no toner remains on the indenter. The measurement was carried out.
Here, the average value of the amount of deformation of the toner when the maximum load is reached is defined as X.

<Coverage of external additive>
The toner was observed using a field emission scanning electron microscope SU8230 (manufactured by Hitachi High-Tech), and image processing was performed to determine the coverage of the external additive. Specifically, the procedure was as follows. Carbon tape was attached to the SEM sample table, and toner was placed on it. The toner was dispersed on the carbon tape by air blowing and introduced into the SEM. First, the magnification was set low, and a field of view in which 40 or more non-overlapping toner particles were seen was photographed. Next, at high magnification, a secondary electron image was acquired for each toner particle in this field of view. At this time, care was taken to deepen the depth of focus, focus on the front of the toner, and add contrast to the extent that there is no overexposure or underexposure. At this time, the external additive was photographed brighter than the surface of the toner base. This was read by ImageJ, an image processing software, and trimmed so that the front surface of the toner was in focus and the toner was reflected in the entire image. At this time, the trimming range was set to 1 μm square or more, and if this was not satisfied, it was excluded from the measurement without performing the following procedure. The trimmed image was binarized by a discriminant analysis method (Otsu's binarization) in the binarization process of image adjustment, and the toner matrix particles and the external additive were identified. By calculating the number of pixels of the external additive for all the pixels, the external additive coverage of one toner particle was calculated. The average value obtained for all the toner particles observed at a low magnification was taken as the external additive coverage of the toner.
An example of SEM measurement conditions is shown below.
[SEM measurement conditions]
Low magnification accelerating voltage: 2.0kV
WD (Working Distance): 15.0mm
Observation magnification: 1000 times high magnification Acceleration voltage: 2.0 kV
WD (Working Distance): 15.0mm
Observation magnification: 15000 times

<Confirmation of the presence of fine particles containing strontium titanate as the main component, calculation of radius R>
The presence of strontium titanate-based fine particles was determined by combining SEM and energy dispersive X-ray analysis images (EDX) to identify the elements. The radius R was calculated by mapping the electronic image of the toner on a spreadsheet software, regarding the cells constituting the contour of the toner particles as coordinates, and determining the coordinates of three points on the contour.
First, a secondary electron image of the toner was acquired using a field emission scanning electron microscope SU8230 (manufactured by Hitachi High-Tech). Carbon tape was attached to the SEM sample table, and toner was placed on it. The toner was dispersed on the carbon tape by air blowing and introduced into the SEM. First, the magnification was set to a low magnification, and a field of view in which 40 or more non-overlapping toner particles were seen was photographed. Next, the magnification was increased, and the front surface of the toner in this field of view was enlarged and photographed. At this time, the magnification was 500,000 times or more, and the number of pixels was 1280 * 960 pixels or more. Furthermore, the energy dispersive X-ray analysis (EDX) of this image identifies the titanium element, the strontium element, and the third element M, and quantifies them in the range of 80% or more of the total projected area of the particles containing these elements. As a result of the analysis, when titanium, strontium, and the third element M are contained, and the total ratio of these two elements is 50% of the total detected metal elements, the fine particles containing strontium titanate as the main component are formed. Judged.
An example of SEM measurement conditions is shown below.
[SEM measurement conditions]
Low magnification accelerating voltage: 2.0kV
WD (Working Distance): 15.0mm
Observation magnification: 1000 times high magnification Acceleration voltage: 12.0 kV
WD (Working Distance): 12.0mm
Observation magnification: 500,000 times

Next, one particle of the external additive is read from the SEM image with the image processing software ImageJ, trimmed so that only one particle containing strontium titanate as the main component is captured, and then the discriminant analysis method (Otsu no Ni). (Value conversion) was used to binarize the background so that the background was white and the particles were black, and the particles were analyzed to fill the voids in the particles.
This binarized image was output as text data, output (mapped) to Excel, and cells with a numerical value of 255 were painted in black (RGB (0,0,0)) color. At this time, if the particles and the background were not separated, they were excluded from the measurement.
The distance per pixel was obtained from the scale of the SEM image, and it was determined whether the maximum length of the particles was 30 nm or more.
A cell whose circumference is not all black is used as the contour portion of the particle, an arbitrary point on the contour serving as a single point reference is set as the reference point A, and the contour of the fine particles located at a linear distance of 15 nm in one direction from the reference point A. Point B, and point C on the contour of the fine particles located at a linear distance of 15 nm in the other direction from the reference point A, the triangular shape formed by the points A, B, and C. The radius of the circumscribed circle was calculated. This was done at all points on the contour to determine the minimum radius R.
These series of operations were performed using proper programming.
This was done for all the strontium titanate-based fine particles seen at high magnification and for all the toners seen at low magnification. The average value was taken for the rest of the obtained R excluding the lower 20% and the upper 20%.

<Frequency of particles satisfying 11 nm ≤ R ≤ 13 nm>
Among the minimum radii R obtained above, particles satisfying 11 nm ≦ R ≦ 13 nm were counted and the frequency was calculated.

<Manufacturing of carriers>
As the core material, 5,000 parts of Mn ferrite particles (weight average diameter: 35 μm) were used.
As a coating material, 300 parts of toluene, 300 parts of butyl cellosolve, acrylic resin solution (composition ratio (molar ratio) methacrylate: methyl methacrylate: 2-hydroxyethyl acrylate = 5: 9: 3, solid content 50% toluene solution, Tg 38 ° C. ) 60 parts, 15 parts of N-tetramethoxymethylbenzoguanamine resin solution (polymerization degree 1.5, solid content 77% toluene solution), and 15 parts of alumina particles (average primary particle diameter 0.30 μm) were dispersed with a stirrer for 10 minutes. The coating solution prepared in the above was used.
The core material and the coating liquid are put into a coating device for coating while forming a swirling flow provided with a rotary bottom plate disc and stirring blades in a fluidized bed, and the coating liquid is applied onto the core material. It was applied. The obtained coating material was calcined in an electric furnace at 220 ° C. for 2 hours to obtain [carrier].

<Manufacturing of developer>
Uniformly apply 7 parts of [Toner 1] to 100 parts of [Carrier] at 48 rpm for 5 minutes using a Tabler mixer (manufactured by Willie et Bacoffen (WAB)) in which the container is rotated and stirred. The mixture was mixed to obtain [Developer 1], which is a two-component developer.
[Developer 2] to [Developer 20] were obtained in the same manner except that [Toner 1] of [Developer 1] was changed to [Toner 2] to [Toner 20].

-Manufacturing of electrophotographic photosensitive member 1-
A coating liquid for the undercoat layer, a coating liquid for the charge generation layer, and a coating liquid for the charge transport layer having the following compositions are sequentially applied and dried on a φ30 mm aluminum cylinder to reduce the thickness to 3.5 μm. A pull layer, a 0.2 μm charge generation layer, and a 20 μm charge transport layer were formed.

[Coating liquid for undercoat layer]
-Alkyd resin: 12 parts by weight (Beckozol 1307-60-EL, manufactured by Dainippon Ink and Chemicals)
-Melamine resin: 8 parts by weight (Super Beccamin G-821-60, manufactured by Dainippon Ink and Chemicals)
-Titanium oxide: 80 parts by weight (CR-EL, manufactured by Ishihara Sangyo Co., Ltd.)
-Methyl ethyl ketone: 250 parts by weight

[Coating liquid for charge generation layer]
-Bisazo pigment of the following structural formula (M): 2.5 parts by weight-Polyvinyl butyral: 0.5 parts by weight (XYHL, made by UCC)
・ Cyclohexanone: 200 parts by weight ・ Methyl ethyl ketone: 80 parts by weight

[Coating liquid for charge transport layer]
Bisphenol Z Polycarbonate: 10 parts by weight (Panlite TS-2050, manufactured by Teijin Chemicals)
-Charge transport material of the following structural formula (N): 7 parts by weight-Tetrahydrofuran: 100 parts by weight-Tetrahydrofuran solution of 1% silicone oil: 1 part by weight (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

Next, a coating liquid for a surface layer having the following composition is sprayed onto a laminate composed of the conductive support / undercoat layer / charge generation layer / charge transport layer by a spray coating method using the coating liquid for the surface layer below. An electrophotographic photosensitive member 1 was obtained by forming a surface layer having a thickness of 2 μm and heating at 150 ° C. for 30 minutes.

[Coating liquid for surface layer]
-Polyarylate resin of the following structural formula (D): 40 parts by weight-Methylol compound of the following structural formula (A): 35 parts by weight-Aluminum oxide: 25 parts by weight (Sumicolundum AA03 (volume average particle size 300 nm), Sumitomo Chemical Made by the company)
-Surfactant: 0.5 parts by weight (BYK-P104, manufactured by Big Chemie)
-Tetrahydrofuran: 1330 parts by weight-Cyclohexanone: 570 parts by weight

-Manufacturing of electrophotographic photosensitive member 2-
The surface layer coating liquid used in the production of the electrophotographic photosensitive member 1 was changed to the following, and the surface layer film thickness was changed to 5 μm, but the electrophotographic photosensitive member was the same as in the production of the electrophotographic photosensitive member 1. It was created.
[Coating liquid for surface layer]
-Polyallylate resin of the structural formula (D): 31.5 parts by weight-Methylol compound of the following structural formula (B): 6 parts by weight-Charge transport material of the structural formula (N): 37.5 parts by weight-Oxidation Aluminum: 25 parts by weight (Sumicolundum AA03 (volume average particle size 300 nm), manufactured by Sumitomo Chemical Co., Ltd.)
-Surfactant: 0.5 parts by weight (BYK-P104, manufactured by Big Chemie)
-Tetrahydrofuran: 1330 parts by weight-Cyclohexanone: 570 parts by weight

-Manufacturing of electrophotographic photosensitive member 3-
The electrophotographic photosensitive member was prepared in the same manner as the electrophotographic photosensitive member 1 except that the coating liquid for the surface layer used in the production of the electrophotographic photosensitive member 1 was changed to the following and the surface layer film thickness was changed to 5 μm. did.
[Coating liquid for surface layer]
-Polyallylate resin of the structural formula (D): 31.5 parts by weight-Methylol compound of the following structural formula (Q): 6.0 parts by weight-Charge transport material of the structural formula (N): 37.5 parts by weight -Aluminum oxide: 25 parts by weight (Sumicolundum AA03 (volume average particle size 300 nm), manufactured by Sumitomo Chemical Co., Ltd.)
-Surfactant: 0.5 parts by weight (BYK-P104, manufactured by Big Chemie)
-Tetrahydrofuran: 1330 parts by weight-Cyclohexanone: 570 parts by weight

The Martens hardness of the photoconductor was determined as follows.
<Martens hardness>
Using Fisherscope H-100 (manufactured by Fisher Instruments) as an evaluation device and a Vickers quadrangular pyramid diamond indenter having a facing angle of 136 ° as an indenter, the indenter was pressed against the surface of the photoconductor under the following conditions.
Final load applied continuously to the indenter (final load): 6 mN
Time to hold the indenter with the final load of 6 mN (holding time): 0.1 seconds Measurement environment: 23 ° C / 55% RH
Measurement points: Distance between centers 10 mm or more, 20 points The Martens hardness value (HMk) was calculated by the following formula from the average value of the indentation depths when the final load of 6 mN was applied to the indenter. In the following formula, HMk indicates the universal hardness value, F _f indicates the final load, and S _f indicates the surface area of the indenter pressed portion when the final load is applied. Further, h _f indicates the pushing depth (mm) of the indenter when the final load is applied.

An image was formed using the prepared two-component developer, and the following performance evaluation was performed.

<< Low temperature fixability >>
A copying test was performed on type 6200 paper (manufactured by Ricoh Co., Ltd.) using a device obtained by modifying the fixing portion of the copying machine Imagio MF2200 (manufactured by Ricoh Co., Ltd.) using a Teflon (registered trademark) roller as the fixing roller.
Specifically, the cold offset temperature (fixing lower limit temperature) was obtained by changing the fixing temperature, and the procedure was carried out according to the following criteria.
The evaluation conditions for the lower limit temperature of fixing were that the linear velocity of the paper feed was 120 mm / sec to 150 mm / sec, the surface pressure was 1.2 kgf / cm ² , and the nip width was 3 mm.
〔Evaluation criteria〕
⊚: The lower limit temperature for fixing is less than 110 ° C.
◯: The lower limit temperature for fixing is 110 ° C. or higher and lower than 125 ° C.
X: The lower limit temperature for fixing is 125 ° C. or higher.

<< Durability >>
In a high-temperature and high-humidity environment (27 ° C., 80% RH), 500,000 images having an image area ratio of 5% were copied by a digital full-color multifunction device Ricoh's imagio Neo 271 modified machine. Next, after printing the entire solid image, the image was visually observed to evaluate the durability.
⊚: No streak-like color loss occurs 〇: Slight streak-like light color loss occurs (less than 5% of the solid image part)
Δ: When streaky light color loss occurs (5% or more and less than 10% of the solid image part)
X: When many streaky light color loss occurs (10% or more of the solid image part) or streak-like dark color loss occurs.

<< Filming of photoconductor (OPC) >>
In a temperature / humidity environment with a temperature of 10 ° C. and a relative humidity of 15%, each toner and photoconductor was evaluated using a tuned evaluation machine of a part of Ricoh's imagio Neo 271 modified machine. The printing speed was evaluated by high-speed printing (45 sheets / minute / A4).
Adhesion to the photoconductor after printing 10,000 5% image area density charts, printing 5,000 1% image area density charts, and printing 10,000 10% image area density charts. The amount of the component was visually evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
〇: Good without adhesion Δ: Cloudy streaks can be confirmed ×: Large cloudy area Note that those evaluated as Δ or higher are at a level where there is no practical problem in terms of filming property.

<< Photoreceptor wear rate >>
In an environment with a temperature of 40 ° C. and a relative humidity of 90%, using a Ricoh imagio Neo 271 remodeling machine, using each toner and photoconductor, an image area ratio of 5% is continuously output for 100,000 sheets. Durability test Film thickness after paper passing test The amount of decrease was measured with an eddy current film thickness meter (Fisher Corp. MMS, manufactured by Fischer).
〔Evaluation criteria〕
⊚: Abrasion amount is less than 1.0 μm 〇: Abrasion amount is 1.0 μm or more and less than 1.5 μm ×: Abrasion amount is 1.5 μm or more

<< Photoreceptor scratches >>
In an environment with a temperature of 40 ° C. and a relative humidity of 90%, using a Ricoh imagio Neo 271 remodeling machine, using each toner and photoconductor, an image area ratio of 5% is continuously output for 100,000 sheets. Durability test Photoreceptor after paper-passing test The occurrence of scratches on the surface was observed with a laser microscope (VK-8500, manufactured by KEYENCE CORPORATION).
◎: No noticeable scratches 〇: Scratches are seen by microscopic observation but do not appear in the image ×: There are large and deep scratches that appear in the image

The results are shown in Tables 2 and 3.

From the results of Tables 2 and 3, in each of the examples, the low temperature fixability, durability, filming of the photoconductor, wear rate of the photoconductor, and scratches on the photoconductor were all at satisfactory levels.

(About Fig. 1)
100A Image forming apparatus 10 Photoreceptor drum 20 Charging roller 42 (K, Y, M, C) Developer housing 43 (K, Y, M, C) Developer supply roller 44 (K, Y, M, C) Developing Roller 45 (K, Y, M, C) Developer 50 Intermediate transfer member 51 Roller 52 Corona charger 60 Cleaning device 70 Static elimination lamp 80 Transfer roller 90 Cleaning device 95 Recording paper L Exposure light (about FIG. 2)
100B Image forming device 10 (K, Y, M, C) Photoreceptor drum 14 Supporting roller 15 Supporting roller 16 Supporting roller 17 Cleaning device 18 Image forming means 21 Exposure device 22 Secondary transfer device 23 Roller 24 Secondary transfer belt 25 Fixation Device 26 Fixing belt 27 Pressurizing roller 28 Reversing device 32 Contact glass 33 First traveling body 34 Second traveling body 35 Imaging lens 36 Reading sensor 49 Resist roller 50 Intermediate transfer body 53 Manual paper feed path 54 Manual feed tray 55 Switching claw 56 Discharge roller 57 Discharge tray 58 Separation roller 62 Transfer roller 120 Tandem type developer 130 Document stand 142 Paper feed roller 143 Paper bank 144 Paper cassette 145 Separation roller 146 Paper feed path 147 Transfer roller 148 Paper feed path 150 Copying device main body 200 Paper feed table 300 Scanner 400 Automatic document transfer device (ADF)
(About Fig. 3)
10 Photoreceptor drum 18 Image forming means 50 Intermediate transfer body 60 Charging roller 61 Developer 62 Transfer roller 63 Cleaning device 64 Static elimination lamp 65 Development position 66 Developer case 67 Developer case 68 Conveyor screw 69 Developer partition 70 Developer 71 Toner Density sensor 72 Development sleeve 73 Development doctor 75 Cleaning blade 76 Toner recovery roller 77 Recovery bias roller 78 Recovery blade 79 Recovery toner transfer screw 80 Transfer roller L Exposure light (about FIG. 4)
10 Photoreceptor drum 40 Developer 52 Corona charger 80 Transfer roller 90 Cleaning device 95 Recording paper 110 Process cartridge L Exposure light

Japanese Patent No. 3949553 Japanese Patent No. 4155108 Japanese Patent No. 5408210 Japanese Unexamined Patent Publication No. 2013-186167 Japanese Unexamined Patent Publication No. 2014-238450

Claims (10)

The image carrier, the charging means for charging the surface of the image carrier, the exposure means for writing an electrostatic latent image on the surface of the charged image carrier, and the latent image formed on the surface of the image carrier are visualized with toner. In an image forming apparatus including a developing means and a transfer means for transferring a toner image on the surface of the image carrier to a transfer target.
The image carrier has a Martens hardness of 185 to 250 N / m ² .
The toner has a load speed of 3.0 × 10 ^-5 N / sec under an environment of 32 ° C. and 40% RH, and the amount of deformation due to micro-pushing when the load reaches 3.00 × 10 ^-4 N. Assuming that the average value is X [μm] and the number average particle size is Dn [μm], the formula 0.13 ≦ X / Dn ≦ 0.16 is satisfied.
The toner further contains silica fine particles and strontium titanate-based fine particles as an external additive, and the strontium titanate-based fine particles are further derived from La, Mg, Ca, Sn and Si. Containing the selected third element M,
An image forming apparatus characterized in that. The image forming apparatus according to claim 1, wherein the coating ratio of the external additive to the toner is 40 to 70%. The image forming apparatus according to claim 1 or 2, wherein the image carrier has a Martens hardness of 200 to 250 N / m ² . The average value X [μm] of the amount of deformation due to the minute pressing and the number average particle size Dn [μm] satisfy the formula 0.15 ≦ X / Dn ≦ 0.16, and the toner is coated with the external additive. The image forming apparatus according to any one of claims 1 to 3, wherein the rate is 55 to 70%. The fine particles containing strontium titanate as a main component have an average particle diameter of 30 nm or more, and in the projected image of the fine particles, any one point on the contour of the fine particles is set as a reference point A, and one of the fine particles from the reference point A. When the point on the contour of the fine particles located at a linear distance of 15 nm in the direction is defined as point B, and the point on the contour of the fine particles located at a linear distance of 15 nm in the other direction from the reference point A is defined as point C. The image according to any one of claims 1 to 4, wherein the average value of the minimum radius R of the circumscribed circles of the triangle formed by the points A, B and C is 11 to 13 nm. Forming device. The image forming apparatus according to claim 5, wherein among the fine particles containing strontium titanate as a main component, particles satisfying the average value of 11 to 13 nm of the minimum radius R occupy 70% by mass or more. The image according to any one of claims 1 to 6, wherein the image carrier has a surface layer, the surface layer contains a filler, and the volume average particle diameter of the filler is 10 to 500 nm. Forming device. The image forming apparatus according to any one of claims 1 to 7, wherein the toner contains an amorphous polyester resin as a binder resin in an amount of 50% by mass or more of the entire toner. The image forming apparatus according to any one of claims 1 to 8, wherein the surface of the fine particles containing strontium titanate as a main component is coated with an organic compound. A charging step of charging the surface of the image carrier, an exposure step of writing an electrostatic latent image on the surface of the charged image carrier, a developing step of visualizing the latent image formed on the surface of the image carrier with toner, and the image. In an image forming method that sequentially includes a transfer step of transferring a toner image on the surface of a carrier to a transfer target.
The image carrier has a Martens hardness of 185 to 250 N / m ² .
The toner has a load speed of 3.0 × 10 ^-5 N / sec under an environment of 32 ° C. and 40% RH, and the amount of deformation due to micro-pushing when the load reaches 3.00 × 10 ^-4 N. Assuming that the average value is X [μm] and the number average particle size is Dn [μm], the formula 0.13 ≦ X / Dn ≦ 0.16 is satisfied.
The toner further contains silica fine particles and strontium titanate-based fine particles as an external additive, and the strontium titanate-based fine particles are further derived from La, Mg, Ca, Sn and Si. Containing the selected third element M,
An image forming method characterized by this.

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